The issue of human nature was already discussed a lot during the Spring and Autumn period and the Warring States period, and some of the excavated pre-Qin texts also refer to Confucian views of human nature. This article analyzes the character “xing” 性 and its implications in the bamboo slips excavated in 1993 in the Chu tombs at Guodian. In the Chu bamboo slips, the character “xing” 性 was written as “sheng” 眚, which is a mixture of the two characters, “xing” 姓 and “xing” 性. The character “xing” 姓 refers to “people” and the character “xing” 性 means “human nature.” Among them, “xing” 性 is believed to be given by Heaven and indicates the essential nature of humans. Confucius claimed that “xing jin xi yuan” 性近習遠 (The nature of humans is similar, but human accumulated practices cause differences), whereas Mencius suggested the view of “xing shan” 性善 (Human nature is good). There is a difference between these two views, since the former is about natural human nature and the latter concerns moral human nature. The Chu bamboo slips are understood as important writings because many of them interpret human nature in natural terms or in moral terms. By studying the conception of human nature in the Chu bamboo slips, we can understand clearly the gap between Confucius and Mencius and its relations of transmission. In short, the Chu bamboo slips show the transitional stage of views on human nature from Confucius to Mencius.