Abstract: Menci had two interpretations of “four virtues”. On the one hand, he pointed out that they referred to sources of humanity, justice, propriety and wisdom. On the other hand, he thought that theywere just humanity, justice, propriety and wisdom. The two interpretations reveal “four virtues” have two connotations. Namely, they are the source and foundation of humanity, justice, propriety and wisdom.These emphasize the implementation. They need the postnatal expansion and cultivation. Menci talked about human nature with virtues. The double connotation of them shows that the good human nature has also double connotation. As the foundation, they show that man has basis for acquiring morals. This is the theory of good nature as the root. The four virtues need to be expanded and cultivated to humanity, justice, propriety and wisdom. This is the cultivation theory of good nature.