In the early morning of May 20, Li Peng signed and announced the "Order of the State Council of the People's Republic of China on the Implementation of Martial Law in Parts of Beijing", which stated: "Starting at 10:00am on May 20, 1989, martial law will be enforced in parts of Beijing. It will be organized and implemented by the Beijing Municipal People's Government, and specific martial law measures will be taken as needed." Subsequently, Beijing Mayor Chen Xitong issued the "Beijing Municipal People's Government Orders" (No. 1, No. 2, and No. 3), which strictly prohibited marches, class strikes, beating, smashing, looting and any other activities that pose an impediment to order.

After martial law was announced, the vast majority of teachers, students, government officials, and citizens condemned it. According to "The Tiananmen Papers", about 200 reports were sent to leaders that day, of which more than 80% expressed puzzlement or openly disapproved of martial law.

On that day, more than one million students and members of the general public stood guard at major entry points into the city, such as Fengtai, Liuliqiao, Shazikou, Hujialou, Gucheng, and Qinghe. Together, they worked to set up roadblocks, block military vehicles, and prevent the martial law military units from entering the city. Wang Dan wrote in his memoirs that at the time, they distributed leaflets to remind the people to pay attention to three things: "First, the People's Liberation Army officers and soldiers are not our true opposition. The People's Liberation Army are the soldiers of the people. At present, they have been deceived to come here without knowing the truth. We must understand and respect the PLA officers and soldiers. 2. We must try our best to help the PLA officers and soldiers to solve their dietary difficulties. 3. During the blockade process, conflicts with PLA officers and soldiers must be avoided at all cost. At the same time, beware there might be people in plainclothes or others with ulterior motives who might beat the PLA soldiers and try to cause trouble."

According to the books "The Big Bang of History: A Complete Record of the June 4th Incident" and "The Tiananmen Papers", citizens at the scene handed out newspapers to military officials explaining the situation in Beijing. Some people also brought food and water to the surrounded soldiers. Regarding people surrounding the troops, Li Peng wrote in his diary: "I didn't expect that troops entering the city would be met with such great resistance. It is certain that news of martial law was leaked in advance."

References: Zhang Wanshu, "The Big Bang of History: A Complete Record of the June 4th Incident"; Wang Dan, "The Memoirs of Wang Dan — From June 4th to Exile"; "The Critical Moment – Li Peng Diaries"; "The Tiananmen Papers"