Zhang Shizhang (Hottinger S. C. Chang) is considered as a "representative of Chinese Christian socialism". Zhang, late in life, summarized his thirty years of thoughts and deeds after becoming a Baptist Christian, calling himself an "evangelist of Jesusism". This article examines Zhang's life and thoughts as well as the historical contexts in which he lived in Republican China and the early People's Republic of China. Emphasis is laid upon how his idea of "Jesusism" was formed and developed out of both the response to contemporary Chinese religio-political contexts and the appropriation of Western theological trends. His notion of "Jesusism" was closely linked to socialism and Christianity, both of which were what mostly concerned Zhang all his life.