Jiang died from leukemia and multiple organ failure in Shanghai at 12:13 p.m., the official Xinhua news agency said.
He was last seen in public on October 1, 2019, taking his place among party elders invited to attend the 70th anniversary celebrations of the founding of the People's Republic of China, and a military parade to mark the occasion, SCMP reported.
Jiang served as the party's general secretary from 1989 to 2002.