Abstract：Yin and Yang is the world outlook of traditional Chinese medicine.The human body is in the dynamic balance of Yin and Yang promoted by Qi. Traditional Chinese medicine believes that the tumor is caused by the deficiency of positive Qi， which leads to the imbalance of Yin and Yang in the human body， and leads to the accumulation of pathological products such as phlegm， blood stasis and toxin. Tumor cells and their microenvironment are a functional whole， and their interaction determines the progression and fate of tumors. It is a new anti-cancer strategy to treat tumor microenvironment， which is very similar to the mechanism of traditional Chinese medicine in balancing human environment， regulating Yin and Yang， multi-system and multi-target tumor treatment. Traditional Chinese medicine has small side effects， wide range of action and good tumor treatment effect. Based on the Yin-Yang theory of traditional Chinese medicine， author expounds the role and mechanism of traditional Chinese medicine in regulating microenvironment in the treatment of tumor from the four aspects of stromal cells， extracellular matrix， signal pathway and vascular growth， so as to provide new ideas for the application of traditional Chinese medicine and integrated traditional Chinese and western medicine in tumor treatment.