Scholars usually held that the study of tracing the origin of Confucianism began with Zhang Taiyan and Hu Shi. In fact, before them, Kang Youwei adopted the method of Dao to comb through the origins of Confucianism and its derivation in the pre-Qin period from the perspective of the evolution of thought. Then, he inspected the relationship between the Confucian classics and Non-Confucian schools of thought, thus putting forward a set of systematic theory. The Enlightenment of Kang Youwei’s research was that the tracing of Confucianism can’t be limited to the original meaning of Confucianism, but also to explore the origin of “Confucianism” as a type of thought and the source of Confucianism’s acceptance in the pre-Qin period. Meanwhile, in tracing the origin of Confucianism, ancient and modern scholars also explored the relationship between Confucian classics and Non-Confucian schools of thought. And due to the different ideological positions and research methods, there are differences in their understanding of the relationship. Therefore, researchers must combine the history of academic thought to examine the form of the relationship between Confucian classics and Non-Confucian schools of thought in various historical periods, and can’t generalize with a certain proposition.