Among 20th century German writers, Brecht was the most actively interested in the research and adaptation of Chinese culture. Via a series of comparisons, this article reveals that his play The Good Person of Sichuan (Der gute Mensch von Sezuan) was in fact based on the Yuan poetic drama A Sister Courtesan Comes to the Rescue (Zhao Pan’er fengyue jiu fengchen 赵盼儿风月救风尘) by Guan Hanqing 关汉卿; in terms of composition and characterization, the work is related to Mengzi’s 孟子 (Mencius) theory of “the tendency of human nature to do good” (xing shan shuo 性善说) as well. This article looks closely at the lessons Brecht drew from the Chinese dramatic arts, and how he applied that knowledge in the creation of epic theater and in the transformation of traditional Western aesthetics. The article explains how the infusion of classical Chinese wisdom, in combination with Brecht’s literary talent, gave added philosophic depth to The Good Person of Sichuan.