Syndrome differentiation and pathogenesis exploration is the key to achieve good effect in the clinic of traditional Chinese medicine （TCM）. Syndrome is a complex and multi-dimensional concept which is affected by many kinds of factors. It is quite consistent with the theory of complex giant system， so it is suitable to use the theory of complex giant system to study the speculative procedure of syndrome and pathogenesis. This paper conducts a comprehensive and in-depth conception exploration through discussing the theory， method and feasibility of using the complex giant system theory to study the speculative procedure of TCM syndrome differentiation and pathogenesis exploration. Through the investigations on the brief introduction of speculative procedure of TCM syndrome differentiation and pathogenesis exploration， the general situation of using modern scientific methods to study TCM syndrome differentiation， the design of using complex giant system to study the speculative procedure of TCM syndrome differentiation and pathogenesis exploration and its prospects， the rationality of the speculative procedure of syndrome and pathogenesis researched by complex giant system theory is analyzed. Using the theory of complex giant system to study the speculative procedure of TCM syndrome differentiation and pathogenesis exploration has feasibility and practical value for the research of TCM syndrome differentiation and pathogenesis theory.