Tang Junyi's research about Xunzi's Tao theory mainly gathered in his book Original Essay of Chinese Philosophy·Original Tao. He thinks that the Tao of Xunzi is specifically the Tao of mankind. This is the most important difference between mankind and the nature. Heaven is the basis of the being of Tao of mankind, which is the Tao of knowledge and behavior, and can provide a stop for man's understanding. Moreover, Tao of mankind consists of two levels of Tao: the Tao of mind, and the Tao of humanity, politics and history. It is the combination of subjectivity and objectivity. On the level of Tao of humanity, politics and history, it contains two dimensions of ideal and reality. At the same time, Tao of mankind also is the Tao of the overall of humanities.