Abstract：The author believes that the pathogenesis discovered by eight principle syndrome differentiation and visceral syndrome differentiation，in essence，is an incomplete manifestation of the thinking on five circuits and six qi by comparing and analyzing the similarities and differences of thinking modes among eight principle syndrome differentiation， visceral syndrome differentiation and five circuits and six qi. Besides the analysis of pathogenesis， in terms of the clinical practice under the guidance of five circuits and six qi， we also needs to pay attention to the factors of time and space and to comprehensively analyzing the pattern of circuits and qi as well as its effect on diseases. Pulse diagnosis has become an important index to prove the joining of qi with circuits. The syndrome differentiation method of five circuits and six qi can better reflect the core idea of "unity of man and nature" in Chinese medicine.