In mid-1986, astrophysics professor Fang Lizhi returned from a position at Princeton University and began a personal tour around universities in China; speaking about liberty, human rights, and separation of powers. Fang was part of a wider undercurrent within the elite intellectual community that thought China's poverty and underdevelopment, and the disaster of the Cultural Revolution, were a direct result of the authoritarian political system and the rigid command economy.

Inspired by Fang and other 'people-power' movements around the world, in December 1986, student demonstrators staged protests against the slow pace of reform.

General secretary Hu Yaobang was blamed for taking a soft attitude and mishandling the protests, thus undermining social stability. He was denounced thoroughly by conservatives. Hu was forced to resign as general secretary on 16 January 1987. Then the party began the "Anti-bourgeois liberalization Campaign", taking aim at Hu, political liberalization and Western-inspired ideas in general. The Campaign stopped student protests and tightened the political environment, but Hu remained popular among progressives in the party, intellectuals, and students.

When Hu Yaobang suddenly died of a heart attack on 15 April 1989, students reacted strongly, most of them believing that his death was related to his forced resignation. Hu's death provided the initial impetus for students to gather in large numbers.

Small spontaneous gatherings to mourn Hu began on 15 April around Monument to the People's Heroes at Tiananmen Square. On the same day, many students at Peking University (PKU) and Tsinghua University erected shrines, and joined the gathering in Tiananmen Square in a piecemeal fashion.

Organized student gatherings began on a small scale in Xi'an and Shanghai on 16 April.

On 17 April, students at the China University of Political Science and Law (CUPL) made a large wreath to commemorate Hu Yaobang. Its laying-party was on 17 April and a larger-than-expected crowd assembled. At 5 pm, 500 CUPL students reached the eastern gate of the Great Hall of the People, near Tiananmen Square, to mourn Hu. The gathering featured speakers from various backgrounds giving public orations commemorating Hu and discussing social problems. However, it was soon deemed obstructive to the operation of the Great Hall, so police tried to persuade the students to disperse.

Starting on the night of 17 April, three thousand PKU students marched from the campus towards Tiananmen Square, and soon nearly a thousand students from Tsinghua joined. Upon arrival, they soon joined forces with those already gathered at the Square. As its size grew, the gathering gradually evolved into a protest, as students began to draft a list of pleas and suggestions (Seven Demands) for the government.

On the morning of 18 April, students remained in the Square. Some gathered around the Monument to the People's Heroes singing patriotic songs and listening to impromptu speeches by student organizers, others gathered at the Great Hall. Meanwhile, a few thousand students gathered at Xinhua Gate, the entrance to Zhongnanhai, the seat of the party leadership, where they demanded dialogue with the leadership. Police restrained the students from entering the compound. Students then staged a sit-in.

On 20 April, most students had been persuaded to leave Xinhua Gate. To disperse about 200 students that remained, police used batons; minor clashes were reported. Many students felt abused by the police, and rumours about police brutality spread quickly. This incident angered students on campus, where those who were not politically active decided to join the protests. Also on this date, a group of workers calling themselves the Beijing Workers' Autonomous Federation issued two handbills challenging the central leadership.

On April 21, students began organizing under the banners of formal organizations.

Hu's state funeral took place on 22 April. On the evening of 21 April, some 100,000 students marched on Tiananmen Square, ignoring orders from Beijing municipal authorities that the Square was to be closed off for the funeral. The funeral, which took place inside the Great Hall and attended by the leadership, was broadcast live to the students. General secretary Zhao Ziyang delivered the eulogy. The funeral seemed rushed, and only lasted 40 minutes, as emotions ran high in the Square. Students wept.

On 22 April, near dusk, serious rioting broke out in Changsha and Xi'an. In Xi'an, arson from rioters destroyed cars and houses, and looting occurred in shops near the city's Xihua Gate. In Changsha, 38 stores were ransacked by looters. Over 350 people were arrested in both cities. In Wuhan, university students organized protests against the provincial government. As the situation became more volatile nationally, Zhao Ziyang called numerous meetings of the Politburo Standing Committee (PSC). Zhao stressed three points: discourage students from further protests and ask them to go back to class, use all measures necessary to combat rioting, and open forms of dialogue with students at different levels of government.

On 23 April, in a meeting of around 40 students from 21 universities, the Beijing Students' Autonomous Federation (also known as the Union) was formed. It elected CUPL student Zhou Yongjun as chair. Wang Dan and Wu'erkaixi also emerged as leaders. The Union then called for a general class boycott at all Beijing universities. Such an independent organization operating outside of party jurisdiction alarmed the leadership.

Zhao's departure to North Korea left Li Peng as the acting executive authority in Beijing. On 24 April, Li Peng and the PSC met with Beijing Party Secretary Li Ximing and mayor Chen Xitong to gauge the situation at the Square. The municipal officials wanted a quick resolution to the crisis and framed the protests as a conspiracy to overthrow China's political system and major party leaders, including Deng Xiaoping. In Zhao's absence, the PSC agreed that firm action against protesters must be taken.

On the morning of 25 April, President Yang Shangkun and Premier Li Peng met with Deng at the latter's residence. Deng endorsed a hardline stance and said an appropriate 'warning' must be disseminated via mass media to curb further demonstrations. The meeting firmly established the first official evaluation of the protests from the leadership, and highlighted Deng's having 'final say' on important issues.

Organized by the Union on 27 April, some 50,000–100,000 students from all Beijing universities marched through the streets of the capital to Tiananmen Square, breaking through lines set up by police, and receiving widespread public support along the way, particularly from factory workers.

The government's tone grew increasingly conciliatory as Zhao Ziyang returned from Pyongyang on 30 April and resumed his executive authority. In Zhao's view, the hardliner approach was not working, and concession was the only alternative. Zhao asked that the press be opened to report the movement positively, and delivered two sympathetic speeches on 3–4 May.

While some 100,000 students marched on the streets of Beijing on 4 May to commemorate the May Fourth Movement and repeat demands from earlier marches, many students were satisfied with the government's concessions. On 4 May, all Beijing universities except PKU and BNU announced the end of the class boycott. Subsequently, the majority of students began to lose interest in the movement.

Students began the hunger strike on 13 May, two days before the highly publicized state visit by Soviet leader Mikhail Gorbachev. Knowing that the welcoming ceremony for Gorbachev was scheduled to be held on the Square, student leaders wanted to use the hunger strike there to force the government into meeting their demands. Moreover, the hunger strike gained widespread sympathy from the population at large and earned the student movement the moral high ground that it sought. By the afternoon of 13 May, some 300,000 were gathered at the Square.

On the morning of 13 May, Yan Mingfu, head of the Communist Party's United Front, called an emergency meeting, gathering prominent student leaders and intellectuals, including Liu Xiaobo, Chen Ziming and Wang Juntao. Yan said the government was prepared to hold immediate dialogue with student representatives, but that the Tiananmen welcoming ceremony for Gorbachev would be cancelled whether the students withdraw or not—in effect removing the bargaining power the students thought they possessed. The announcement sent the student leadership into disarray.

The students remained in the Square during the Gorbachev visit; his welcoming ceremony was held at the airport. The Sino-Soviet summit, the first of its kind in some 30 years, marked the normalization of Sino-Soviet relations, and was seen as a breakthrough of tremendous historical significance for China's leaders. However, its smooth proceedings was derailed by the student movement; this created a major embarrassment ("loss of face") for the leadership on the global stage, and drove many moderates in government onto a more 'hardliner' path. The summit between Deng and Gorbachev took place at the Great Hall of the People amid the backdrop of commotion and protest in the Square.

On the evening of 17 May, the PSC met at Zhongnanhai to finalize plans for martial law. At the meeting, Zhao announced that he was ready to "take leave", citing he could not bring himself to carry out martial law. The elders in attendance at the meeting, Bo Yibo and Yang Shangkun, urged the PSC to follow Deng's orders. Zhao did not consider the inconclusive PSC vote to have legally binding implications on martial law; Yang Shangkun, in his capacity as Vice Chairman of the Central Military Commission, went on to mobilize the military to move into the capital.

The situation seemed intractable, so the weight of taking decisive action fell on paramount leader Deng Xiaoping. Matters came to a head on 17 May, during a Politburo Standing Committee meeting at Deng's residence. At the meeting, Zhao Ziyang's concessions-based strategy was thoroughly criticized.

The movement, on the wane at the end of April, now regained momentum. By 17 May, as students from across the country poured into the capital to join the movement, protests of varying sizes were occurring in some 400 Chinese cities. Students demonstrated at provincial party headquarters in Fujian, Hubei, and Xinjiang. Without a clearly articulated official position from the Beijing leadership, local authorities did not know how to respond. Because the demonstrations now included a wide array of social groups, each carrying its own set of grievances, it became increasingly unclear with whom the government should negotiate, and what the demands were.

Li Peng met with students for the first time on 18 May in an attempt to placate public concern over the hunger strike. Li Peng said the government's main concern was sending hunger strikers to hospital. The discussions were confrontational and yielded little substantive progress or dialogue, but gained student leaders prominent airtime on national television.

In the early morning of 19 May, Zhao Ziyang went to Tiananmen in what became his political swan song. He was accompanied by Wen Jiabao. Li Peng also went to the Square, but left shortly thereafter. At 4:50 am Zhao made a speech with a bullhorn to a crowd of students, urging the students to end the hunger strike. He told the students that they were still young and urged them to stay healthy and not to sacrifice themselves without due concern for their futures. Zhao's emotional speech was applauded by some students.

On 19 May, the PSC met with military leaders and party elders. Deng presided over the meeting and said that martial law was the only option. At the meeting Deng declared that he was 'mistaken' in choosing Hu Yaobang and Zhao Ziyang as his successors, and resolved to remove Zhao from his position as general secretary. Deng also vowed to deal resolutely with Zhao's supporters and begin propaganda work.

The Chinese government declared martial law on 20 May and mobilized at least 30 divisions from five of the country's seven military regions. At least 14 of PLA's 24 army corps contributed troops. As many as 250,000 troops were eventually sent to the capital, some arriving by air and others by rail.

The army's entry into the city was blocked at its suburbs by throngs of protesters. Tens of thousands of demonstrators surrounded military vehicles, preventing them from either advancing or retreating. Protesters lectured soldiers and appealed to them to join their cause; they also provided soldiers with food, water, and shelter. Seeing no way forward, the authorities ordered the army to withdraw on 24 May. All government forces retreated to bases outside the city. While the Army's withdrawal was initially seen as 'turning the tide' in favour of protesters, in reality mobilization took place across the country for a final assault.

In Hong Kong on 27 May, over 300,000 people gathered at Happy Valley Racecourse for a gathering called Democratic songs dedicated for China. Many Hong Kong celebrities sang songs and expressed their support for the students in Beijing.

A procession of 1.5 million people, one fourth of Hong Kong's population, led by Martin Lee, Szeto Wah and other organization leaders, paraded through Hong Kong Island. Across the world, especially where ethnic-Chinese lived, people gathered and protested. Many governments, including those of the United States and Japan, issued travel warnings to China.

On 1 June, Li Peng issued a report titled "On the True Nature of the Turmoil", which was circulated to every member of the Politburo. The report aimed to persuade the Politburo of the necessity and legality of clearing Tiananmen Square by referring to the protestors as terrorists and counterrevolutionaries. The report stated that turmoil was continuing to grow, the students had no plans to leave, and they were gaining popular support.

On 2 June, the movement saw an increase in action and protest, solidifying the CPC's decision that it was time to act. Protests broke out as newspapers published articles that called for the students to leave Tiananmen Square and end the movement. Many of the students in the Square were not willing to leave and were outraged by the articles.

On 2 June, Deng Xiaoping and several party elders met with the three remaining politburo standing committee members, Li Peng, Qiao Shi and Yao Yilin, after Zhao Ziyang and Hu Qili had been ousted; the committee members agreed to clear the Square so "the riot can be halted and order be restored to the Capital." They also agreed that the Square needed to be cleared as peacefully as possible, but if protesters did not cooperate, the troops were authorized to use force to complete the job. That day, state-run newspapers reported that troops were positioned in ten key areas in the city.

On the evening of 2 June, reports that an army trencher ran into four civilians, killing three sparked fear that the army and the police were trying to advance into Tiananmen Square. Student leaders issued emergency orders to set up roadblocks at major intersections to prevent the entry of troops into the center of the city.

On the morning of 3 June, students and residents discovered troops dressed in plainclothes trying to smuggle weapons into the city. The students seized and handed the weapons to Beijing Police. The students protested outside the Xinhua Gate of the Zhongnanhai leadership compound and the police fired tear gas. Unarmed troops emerged from the Great Hall of the People and were quickly met with crowds of protesters. Several protesters tried to injure the troops as they collided outside the Great Hall of the People, forcing soldiers to retreat, but only for a short while.

On the evening of 3 June, state-run television warned residents to stay indoors but crowds of people took to the streets, as they had two weeks before, to block the incoming army. PLA units advanced on Beijing from every direction—the 38th, 63rd and 28th Armies from the west, the 15th Airborne Corps, 20th, 26th and 54th Armies from the south, the 39th Army and the 1st Armored Division from the east and the 40th and 64th Armies from the north.

At 8:30 pm, army helicopters appeared above the Square and students called for campuses to send reinforcements.

At 10 pm, the founding ceremony of the Tiananmen Democracy University was held as scheduled at the base of the Goddess of Democracy.

At about 10 pm the 38th Army began to open fire upward into the air as they traveled east on West Chang'an Avenue toward the city centre. They initially intended the warning shots to frighten and disperse large crowds gathering to stop their progress. This attempt failed. The earliest casualties occurred as far west as Wukesong, where Song Xiaoming, a 32-year-old aerospace technician, was the first confirmed fatality of the night. Several minutes later, when the convoy eventually encountered a substantial blockade somewhere east of the 3rd Ring Road, they opened automatic rifle fire directly at protesters. The crowds were stunned that the army was using live ammunition and reacted by hurling insults and projectiles. The troops used expanding bullets, prohibited by international law for use in warfare, which expand upon entering the body and create larger wounds.

At 10:16 pm, the loudspeakers controlled by the government warned that troops may take "any measures" to enforce martial law.

By 10:30 pm, news of bloodshed to the west and south of the city began trickling into the Square, often told by witnesses drenched in blood. At midnight, the students' loudspeaker announced news that a student had been killed on West Chang'an Avenue, near the Military Museum and a somber mood settled on the Square. Li Lu, the deputy commander of the student headquarters, urged students to remain united in defending the Square through non-violent means.

At about 10:30 pm, the advance of the army was briefly halted at Muxidi, about 5 km west of the Square, where articulated trolleybuses were placed across a bridge and set on fire. Crowds of residents from nearby apartment blocks tried to surround the military convoy and halt its advance. The 38th Army again opened fire, inflicting heavy casualties.

At about 12:15 am, a flare lit up the sky and the first armored personnel vehicle appeared on the Square from the west.

At 12:30 am, two more APCs arrived from the South. The students threw chunks of concrete at the vehicles. One APC stalled, perhaps by metal poles jammed into its wheels, and the demonstrators covered it with gasoline-doused blankets and set it on fire. The intense heat forced out the three occupants, who were swarmed by demonstrators. The APCs had reportedly run over tents and many in the crowd wanted to beat the soldiers. But students formed a protective cordon and escorted the three men to the medic station by the History Museum on the east side of the Square.

At about 1:30 am, the vanguard of the 38th Army and paratroopers from the 15th Airborne Corps arrived at the north and south ends of the Square, respectively. They began to seal off the Square from reinforcements of students and residents, killing more demonstrators who were trying to enter the Square. Meanwhile, the 27th and 65th Armies poured out of the Great Hall of the People to the west and the 24th Army emerged from behind the History Museum to the east. The remaining students, numbering several thousand, were completely surrounded at the Monument of the People's Heroes in the center of the Square.

At 2 am, the troops fired shots over the heads of the students at the Monument. The students broadcast pleadings back toward the troops: "We entreat you in peace, for democracy and freedom of the motherland, for strength and prosperity of the Chinese nation, please comply with the will of the people and refrain from using force against peaceful student demonstrators".

At about 2:30 am, several workers near the Monument emerged with a machine gun they had captured from the troops and vowed to take revenge. They were persuaded to give up the weapon by Hou Dejian. The workers also handed over an assault rifle without ammunition, which Liu Xiaobo smashed against the marble railings of the Monument.

At 3:30 am, at the suggestion of two doctors in the Red Cross camp, Hou Dejian and Zhuo Tuo agreed to try to negotiate with the soldiers. They rode in an ambulance to the northeast corner of the Square and spoke with Ji Xinguo, the political commissar of the 38th Army's 336th Regiment, who relayed the request to command headquarters, which agreed to grant safe passage for the students to the southeast. The commissar told Hou, "it would be a tremendous accomplishment, if you can persuade the students to leave the Square.

At 4 am, the lights on the Square suddenly turned off, and the government's loudspeaker announced: "Clearance of the Square begins now. We agree with the students' request to clear the Square." The students sang The Internationale and braced for a last stand. Hou returned and informed student leaders of his agreement with the troops.

At 4:30 am, the lights relit and the troops began to advance on the Monument from all sides.

At about 4:32 am, Hou Dejian took the student's loudspeaker and recounted his meeting with the military. Many students, who learned of the talks for the first time, reacted angrily and accused him of cowardice.

The soldiers initially stopped about 10 meters from the students. Feng Congde took to the loudspeaker and explained that there was no time left to hold a meeting. Instead, a voice vote would decide the collective action of the group. Although the vote's results were inconclusive, Feng said the "gos" had prevailed. Within a few minutes, at about 4:35 am, a squad of soldiers in camouflaged uniform charged up the Monument and shot out the students' loudspeaker. Other troops beat and kicked dozens of students at the Monument, seizing and smashing their cameras and recording equipment. An officer with a loudspeaker called out "you better leave or this won't end well."

At about 5:10 am, the students began to leave the Monument. They linked hands and marched through a corridor to the southeast, though some departed through the north. Those who refused to leave were beaten by soldiers and ordered to join the departing procession.

Just past 6 am on June 4, as a convoy of students who had vacated the Square were walking westward in the bicycle lane along Chang'an Avenue back to campus, three tanks pursued them from the Square, firing tear gas and one drove through the crowd, killing 11 students, injuring scores.

Having removed the students from the square, soldiers were ordered to relinquish their ammunition, after which they were allowed a short reprieve from 7 am to 9 am.

On the morning of 4 June, police forcibly broke up the student demonstration taking place in Chengdu's main square. The resulting violence killed eight people, and injured hundreds.

The suppression on June 4 marked the end of a period of relative press freedom in China and media workers—both foreign and domestic—faced heightened restrictions and punishment in the aftermath of the crackdown. State media reports in the immediate aftermath were sympathetic to the students. As a result, those responsible were all later removed from their posts.

In Shanghai, students marched on the streets on 5 June and erected roadblocks on major thoroughfares. Factory workers went on a general strike and took to the streets as well; railway traffic was also blocked. Public transport was also suspended and prevented people from getting to work.

On 5 June, the suppression of the protest was immortalized outside of China via video footage and photographs of a lone man standing in front of a column of tanks leaving Tiananmen Square via Chang'an Avenue. The "Tank Man", as it became known, became one of the most iconic photographs in the 20th century. As the tank driver tried to go around him, the "Tank Man" moved into the tank's path. He continued to stand defiantly in front of the tanks for some time, then climbed up onto the turret of the lead tank to speak to the soldiers inside. After returning to his position in front of the tanks, the man was pulled aside by a group of people.

On 7 June, students from major Shanghai universities stormed various campus facilities to erect biers in commemoration of the dead in Beijing. The situation gradually came under control without use of deadly force.

Similar scenes unfolded in Nanjing. On 7 June, hundreds of students staged a blockade at the Nanjing Yangtze River Bridge as well as the Zhongyangmen Railway Bridge. They were persuaded to evacuate without incident later that day, though returned the next day to occupy the main railway station and the bridges.

On 13 June 1989, the Beijing Public Security Bureau released an order for the arrest of 21 students who they identified as leaders of the protest. These 21 most wanted student leaders were part of the Beijing Students Autonomous Federation which had been an instrumental student organization in the Tiananmen Square protests. Though decades have passed, the Most Wanted list has never been retracted by the Chinese government.

At 4:30 pm on 3 June, the three politburo standing committee members met with military leaders, Beijing Party Secretary Li Ximing, mayor Chen Xitong, and State Council secretariat Luo Gan, and finalized the order for the enforcement of martial law.

The stunning success of the March forced the government into making concessions and meeting with student representatives. On 29 April, State Council spokesman Yuan Mu met with appointed representatives of government-sanctioned student associations. While the talks discussed a wide range of issues, including the Xinhua Gate incident and freedom of the press, they achieved few substantive results. Independent student leaders such as Wuer Kaixi refused to attend.