Abstract：The pathogenesis and metastasis of tumor were analyzed from the perspective of membrane system in Chinese medicine. The membrane system is composed of the gap membrane- like tissues between each zang- fu organ and is widely distributed in the human body. It can communicate with the whole body qi，blood，body fluid and essence，and it performs its functions when there is free flow. The membrane system is susceptible to the invasion of pathogenic factors. More and more studies have proved that the presence of membrane is related to the development， transmission and metastasis of diseases. The occurrence and development of tumor is also closely related to the membrane，and cancer cells can spread up and down along the membrane. Based on the analysis of the relationship between membrane system and the occurrence and development of tumor，it is suggested that the method of rectifying and unblocking can be used to treat malignant tumor.