The thought of “preventive treatment of disease” in traditional Chinese medicine(TCM) has a long history.Under the guidance of the theory of “preventive treatment of disease”，it is of positive significance to expound on the concept and principle of “Tong” in TCM.It is important for the body to remain unobstructed because the body is easy to get sick in a state of obstruction.When the intestine is obstructed，it is easy to cause constipation.Numbness occurs when the channels and collaterals are obstructed.In addition，it is easy to catch a cold if the interstices are insecure.The physiological functions of intestines，channels and collaterals，and interstices，the etiology and pathogenesis of obstruction，and the therapy of diseases related to obstruction were analyzed from the perspective of TCM.The theory of “preventive treatment of disease” in TCM emphasizes the harmony between man and nature.At present，there are many ways for “preventive treatment of disease”，and the key is to keep the human body in the state of “tong”.This study hopes that the concept of “preventive treatment of disease” in TCM can provide new ideas in preventing obstruction caused by various factors in daily life.