The"Body-Qi theory"is an important part of the theoretical system of Huangdi Neijing and the theory of"Syn-drome Differentiation &Targeted Therapy"is a guiding theory for the future development of TCM put forward by Academician Tong Xiaolin.By explaining the connotation of the theory of"Body-Qi theory"and"Syndrome Differentiation &Targeted Therapy",this paper connects modern TCM's"Syndrome Differentiation &Targeted Therapy"with traditional TCM's"Body-Qi theory",and holds that the substantive theoretical basis of"Syndrome Differentiation &Targeted Therapy"is"Body-Qi theory".To explore the essence of"Syndrome Differentiation &Targeted Therapy"and find its theoretical source,and lay a theoretical foundation for modem Chinese medicine to better understand and apply"Syndrome Differentiation &Targeted Therapy".