By analyzing the historical background and process of publication of An Illustrated Introduction of Taijiquan(hereinafter referred to as the Introduction for short) written by CHEN Xin, collated the information about the works and people in relation to CHEN style Taijiquan before and after the publication of the Introduction, and put forward the following opinions: the Introduction finished by CHEN Xin before his death is not only the earliest classic CHEN’s Taijiquan teaching textbook found so far in China, but also an important work for studying the theory and practice of traditional Taijiquan in Chenjiagou, Wen county in the early Republic of China; this posthumous work is a comprehensive work on the ideological essence and theoretical innovation of CHEN Xin Taijiquan, which are shown in establishing the basic concepts of CHEN style Taijiquan, extracting the cultural thoughts of Taijiquan, putting forward the technical characteristics of the wire wrapping power approach, innovating on the "thirteen-move" proceduralized teaching method; for a long time, the Introduction was not commonly recognized and objectively evaluated by academic community, even some of its academic thoughts and theories were obviously twisted and falsified, whose reason was directly related to that they contradicted the view in "the theory of boxing being created by CHEN Yu-ting" put forward by TANG Hao and CHEN Zi-ming since the early 1930 s.