Yuan Mei
Cheng carried on the family business in selling salt. Wu Jingzi (), who hated salt merchants, also became his friend. When the two became friends, Cheng was 24 and Wu was 41. But their friendship wasn't influenced by the difference of age and their sincere friendship lasted a lifetime. He often discussed academic problems with scholars. In his early life, Cheng made friends with Shang Pan () and Yuan Mei (). In his later years, he often traveled with Zhu Yun () and Dai Zhen (). Cheng was so dedicated in social and cultural work that he had no time to manage his business and eventually went bankrupt.