程伊川的心性論體系具有豐富的思想內涵，其中「心」之概念具有複雜的結構，包括「性」「形」「外物」三個因素，其中「形」「外物」決定了「心」的後天經驗性，但「性」為「心」之本質規定，又表明了「心」具有形上的規定，伊川亦是在此層面肯定心、性、理「為一」。基於此，本文又對伊川所籠統認可的「情出於性」之背景下的「善惡」與「性」之關係問題以及「思慮未萌」之「未發」都進行了探討，以期對伊川心性論的結構有所釐清。

Cheng Yichuan’s thought on mind and nature has abundant thinking connotation. The structure of mind in his thought is complex. Mind includes three factors—nature, xing and external things. Among them the factors of xing and external things decide the posteriority of mind. However, the nature is the essence of mind, which indicates mind has metaphysical nature. It is in this sense that Yichuan approves that mind, nature and li are identical. Based on the above, this paper also discusses the problem of good and evil and the problem of weifa in order to clarify the structure of Yichuan’s thought on mind and nature.