This article introduces Prof. Lu Deming’s experience in differentiating and treating postoperative metastatic breast cancer. It is believed that deficiency of healthy qi and residual poison are the etiology and pathogenesis; reinforcing the healthy qi and regulating yin and yang are the therapeutic principles; combination of diseases and syndromes differentiation, and the flexible application of classical formula should be paid attention to in clinic. Simultaneously, regulating emotions and diet should be emphasized. One prove case is presented.