"Tendency of disease" is an important concept in the theory of traditional Chinese medicine （TCM）. It was born out of and rooted in the thinking of "conducting by tendency" of ancient Chinese philosophy， meaning that the development and change of humans and nature have their own inevitable laws and dynamic tendencies. Based on the concept of holism and constant motion， the basic definition of "tendency"， the origin of the idea， the influence factors and related concepts were analysed， to grasp the overall connection in the dynamic changes in space and time， and to find a scientific and comprehensive objective law of development. The "tendency" was regarded as dynamic forces in the complex system， when

yin

and

yang

harmonized， called normal tendency； when fail to keep normal， called disease tendency； the season have sequential tendency， the earth has geographical tendency， people have body tendency， medications have medical tendency， and pulse has pulse tendency. Then the "eight methods of treating tendency" were summed up as observing tendency， evaluating tendency， waiting for tendency， accumulating tendency， favoring tendency， counteracting tendency， preventing tendency， and borrowing tendency， and condenses the methodo-logical thinking of "treatment according to disease tendency"， with a view to re-understanding the internal logic of TCM diagnosis and treatment， and providing metaphysical contemplation and exploration for the construction of a

new paradigm of TCM syndrome differentiation and treatment.