明代理學家王廷相的「性論」，與宋代以來許多儒者論點不同，相當具有特色。其「性有善惡」的思想，一方面來自於其對「氣」的看法，一方面又吸收歷來「性三品」的論述，建構了一套具有現實意義的「性論」。本文分為三個部分：首先，上溯王廷相「氣論」，探討其「氣」與「性」的關係。其次，通過王廷相駁「性善」說、性的上中下之別，以及性的「習成」三方面，探討其「性」與「善惡」之間的問題。最後，深入分析王廷相論「性」的層次，將「性」分成天生的為善為惡能力，以及本有的人心、道心兩種意義；並與「性三品論」與「聖愚觀」結合，見其理論中上、中、下人之間「性」的差異：就聖人、中人來說，其「性論」並不離開宋儒「性善」宗旨；但就下愚來說，本無任何為善能力，否定了其天賦善性，是與「性善」說最大的差異所在

The Ming Dynasty's Confucian Scholar Wang Tingxiang's theory of ＂human nature＂ is special and different from many Confucianists after Song Dynasty. His theory of ＂human nature is good and evil＂ is of realistic meaning. On the one hand it is based on his ＂qi-based philosophy＂; on the other hand it inherits previous theory of ＂the three qualities of human nature＂. The topic will be approached from three aspects: First, to confer Wang Tingxiang's theory of ＂qi＂, finding out the relation between ＂qi＂ and ＂human nature＂. Secondly, to discuss the connection between Wang Tingxiang's ＂human nature＂ with ＂good and evil＂ from analyzing Wang's attitude against the theory of ＂human Nature is Good＂, superior, inferior and medium human Nature, and a opinion about human Nature can be learned and cultivated. Thirdly, to differentiate two meanings about the gradations of ＂human nature＂: can do good or evil things naturally, and the natural mind of dao and the mind of man. Combining with the theory of ＂the three qualities of human nature＂, we can see the difference of ＂human nature＂ between superior, inferior and medium people: Wang Tingxiang's theory of ＂human nature＂ have no difference with Song Dynasty's Confucian Scholars on talking about saints and medium people. But Wang Tingxiang denies inferior people having good ＂human nature＂ or any ability of doing good things. At this point, it's quite apart from the theory of ＂human nature is good＂