Abstract： This paper introduces the experience of Professor CHAI Kequn treating breast cancer with the theory of treating disease through emotional therapy. The relationship between emotional factors and the occurrence and development of malignant tumors， as well as the application of emotional factors in treating tumors are analyzed， that is， emotion pathopoiesis and treating disease through emotional therapy. Based on the the etiology and pathogenesis of breast cancer， this paper puts forward four principles and four methods in Chinese medicine for the prevention and treatment of tumors，and emphasizes that the attention should be paid to the treatment methods of regulating spirit in the whole course as well as soothing the liver and resolving constraint when applying the theory of treating disease through emotional therapy in treating breast cancer.