[1] He was a researcher at the Chinese Academy of Social Sciences at the time of the Tiananmen massacre in 1989, and he tried in vain to persuade students to leave Tiananmen Square before the army suppression, as they refused to believe the soldiers would open fire on peaceful student protesters.
[2][3] Investigated after the protests as a student sympathiser, he refused to admit guilt.
[3][4] Xu is an expert on Western social theories, including Marxism and the Frankfurt School, and a noted historian of the Cultural Revolution.
[citation needed] He is one of the signatories of the Charter 08, a manifesto to promote political reform and democratization in China.
[4] In 2014, Xu was awarded Sweden's Human rights Olof Palme Prize.