Abstract： The paper introduces Buzhong Yiqi tang and the specific application of it by Prof. WANG Xixing from three aspects： the origin of Buzhong Yiqi tang， WANG's experience in treating tumor- related diseases and WANG's outpatient cases. In this paper， Prof. WANG's ideas and experience of using Buzhong Yiqi tang clinically to treat leukopenia and moderate- to- severe bone marrow suppression， cancer fatigue， cancer fever， non- healing of malignant tumor postoperative wound， malignant tumor liver metastasis， malignant tumor bone metastasis， rectal cancer postoperative impotence after malignant tumor chemotherapy were analyzed，so as to provide some ideas and experience for the clinical application of Buzhong Yiqi tang in the treatment of tumor-related diseases.