Bao Tong, who served as secretary to the former Communist Party leader Zhao Ziyang, died on Wednesday morning in Beijing.
He was 90.
Writing on social media, his children said Bao passed away peacefully.
Bao was born in Zhejiang province in 1932 and grew up in Shanghai. He was a member of the 13th Central Committee of the Communist Party. Both Zhao and Bao fell from grace over the 1989 student protests on the mainland.