The study of Li Ao's thought in the present academic circle mainly focuses on tracing back the origin of his thoughts and discussing his influence on Neo-Confucianism. Many contradictions in his thought are often attempted to be solved by introducing external ideological resources. This approach neglects the independence of Li Ao's thoughts. The relationship of nature and emotion is the key to understand his thought, and it is not the the relationship of source-flow or ti-yong, but of causality, by which the contradiction between good nature and evil emotion can be avoided. Furthermore, by rethinking the categories of "moving-stillness", "unmoving-moving" and "gan-ji", we can understand the feature and function of nature and emotion respectively. On this basis, Li Ao's theory of cultivation can also be re-understood. His theory of "jiranbudong" does not have any meaning of "stillness", and his theory of cultivation does not take "stillness" as its gist, but "zhi" of mind is the core.