It is mainly composed of diagnostic methods and syndrome differentiation. Diagnostic methods are the methods used to examine patients and collect pathological data, mainly including inspection, listening and olfaction, inquiry and pulse-taking, known as the four diagnostic methods. Syndrome differentiation means to synthesize and analyze the pathological data so as to decide the nature of the syndrome. The theory and methods for syndrome differentiation include syndrome differentiation with eight principles, syndrome differentiation of causes,syndrome differentiation of qi,blood and body fluid,syndrome differentiation of viscera, syndrome differentiation of meridians, syndrome differentiation of six meridians, syndrome differentiation of defensive qi, qi, nutrient qi and blood as well as syndrome differentiation of triple energizer. Various ways to differentiate syndrome are the theory and methods for analyzing and understanding the nature of disease. They, though with their own characteristics and specific range, supplement each other and together form the syndrome differentiation system in TCM.

Concept of organic wholeness is, the main characteristics of the theoretic system of TCM which is thoroughly demonstrated by the diagnostics of TCM. In diagnosing pathological conditions, deciding the category of disease and differentiating syndrome, TCM emphasizes the entirety.