Cheng Siyuan, male, Han nationality, is a native of Binyang, Guangxi Zhuang Autonomous Region. He was born in 1908 and received a Ph.D. from Rome University.
Early in his career, Cheng was actively involved in the KMT. He began as secretary to Bai Chongxi of the KMT National Military Council. He later served as a standing committee member of the KMT 6th Central Executive Committee. In 1965, he became chairman of the Association for Promoting Peaceful Reunification of China and later presided over the Council for Promoting Peaceful Reunification of China. He then became a standing committee member of the CPPCC National Committee. In 1998, he became president of the Taiwan Studies Society.
Cheng was a standing committee member of the 5th and 6th CPPCC National Committees. He also was a standing committee member of the 6th NPC and was elected vice-chairman of 8th and 9th NPC Standing Committees.