This study contains an explication of Chuanshan’s interpretation of “Mencius. Jing Qi Xin Zhe Zhang” (“Chapter on Those True to the Heart”), a chapter in which Mencius dwells upon being true to the heart, knowing human nature, and knowing about “Tien” (the heavens). The concepts of heart, human nature and the heavens are vital to the chapter. However, in his interpretation, Chu Hsi quoted the explications of two scholars on heart, human nature and the heavens to convey his own interpretations, one of which was Chen Tse, who held that “heart, human nature, and the heavens are of one origin.” The other explication came from Chang Tsai, whom Chu Hsi quoted saying “the original emptiness is the name of the heavens, spiritualization is the name of Tao” in order to interpret the heart, human nature and the heavens. In Wang’s attempt to conjoin the interpretations of these two scholars, he placed heavier emphasis on one rather than the other, namely, he took after Chang Tsai’s interpretation of the spiritualization of Tien and Tao, and discarded Chen Tse’s opinion that the heart, human nature, and the heavens are of one origin. It was evident that Wang relied more heavily on the theory of Chi, and it may also be said that Wang employed the thought of Chi to replace the theoretical thought advocated by Chen and Chu. Moreover, Wang considered Chu Hsi’s interpretation of “knowing the ways of the world” as “knowing human nature” eccentric, but did not express dissent, because Wang’s understanding of “knowing the ways of the world” is not to detach oneself from morals and material things, and not to detach oneself from spiritualization. It was his opinion that, in this way, Mencius’ thought could be differentiated from the detachment theories that are considered as more appropriate to Buddhist thought and the thought of Laozi. The emphasis on thought of Chi was Wang’s contribution to the interpretation of Mencius beyond the teachings of Chen and Chu.