This article discussed the method, structure and evolution of Yun Tieqiao’s theory about liver based on his literature works. It can be concluded that Yun’s theotry evolution can be divided into two periods. The first period was based on “Qi transformation” theory, which argues that the liver is not a concrete organ but the production of spring qi. The function of liver is the result of the transformation of spring qi. In the second period, Yun incorporated western physiology and pathology into Traditional Chinese Medicine(TCM). He further explained TCM terms “liver stores blood” and “liver stagnation” from the angle of dissect physiology and neural physiology in western medicine. Also, he connected the function of liver——qi transformation with the anatomic morphology of liver. Therefore, he laid pathology foundation for the theory of “liver governs the free flow of qi” by firstly examined the pathogenesis of liver stagnation and then observed the function of it. The evolution of Yun’s theory has been contributed greatly to the research of liver, doctrine of organ manifestations and TCM theories.