At present, breast cancer treatment is comprehensive, including surgery first if surgery is possible, followed by chemotherapy according to pathology and immunohistochemistry, radiotherapy if there is lymph node metastasis, and endocrine therapy according to hormone receptor status, as well as immune support and Chinese medicine. Neoadjuvant chemotherapy can also be used if surgery is temporarily not possible, and surgery and subsequent treatments can be performed after the tumor shrinks. Surgery is a local treatment, while chemotherapy and radiotherapy damage and kill some normal cells while killing tumor cells, which makes human immunity suffer a great blow. For many years, people have been dreaming of a treatment method that can target the difference between tumor cells and normal cells, attacking only tumor cells without affecting normal cells, so that the efficacy of treatment can be increased with minimal toxic side effects. With the rapid development of science and technology related to basic and clinical medicine, this dream has been realized – biomolecular targeted therapy for tumors was born and has been applied in clinical treatment of breast cancer through trials. Molecular targeted therapy, also known as “biological missile” therapy, is designed to target the cancer-causing sites at the cellular molecular level, and the drugs will specifically select to combine with these cancer-causing sites to cause the specific death of tumor cells with little effect on normal tissue cells. In the development of breast cancer, the oncogene HER-2 plays an important role in the regulation of cell growth, development and differentiation. Abnormalities in this gene have become an important indicator for clinical assessment of breast cancer malignancy and postoperative prognostic risk. Approximately 25-30% of breast cancer patients are HER-2 positive, and these patients have increased aggressiveness of tumor cells, are prone to early recurrence and metastasis, have significantly shorter survival, and are relatively insensitive to endocrine therapy and chemotherapy. Trastuzumab-Herceptin is the first humanized monoclonal antibody for clinical use. Its mechanism of action is to specifically inhibit tumor cell proliferation and block tumor cell signaling after binding to HER-2 receptor. Herceptin has high affinity and specificity against HER-2 protein, and the drug has additive synergistic effects with a variety of chemotherapeutic and endocrine agents to increase antitumor potency. Large-scale clinical trials have demonstrated that Herceptin combined with chemotherapy can significantly improve patients’ disease-free survival and overall survival time, and can reduce the risk of recurrence by 39%-52% for breast cancer patients based on conventional radiotherapy, and combined chemotherapy can also reduce the risk of death by 33%. In addition, it is well tolerated as adjuvant therapy with fewer side effects, especially the incidence of congestive heart disease is less than 4%, so it is useful for Therefore, it is a milestone in the treatment of HER-2 positive patients. Clinical treatment guidelines for breast cancer patients in China and abroad now recommend the inclusion of Herceptin in the adjuvant treatment of HER-2-positive breast cancer. Therefore, the new principle of comprehensive breast cancer treatment should be surgery followed by chemotherapy and/or combination of biologic targeted therapy, radiotherapy and endocrine therapy for those who can be operated, and supplemented by immune support and TCM modulation and treatment. Molecular targeted therapy is the most active part of breast cancer treatment research in recent years and may become the main direction of breast cancer drug development in the future. It is hoped that more molecularly targeted drugs will be used in the clinic to bring benefits to more breast cancer patients. Currently, Herceptin is mostly used together with chemotherapy, especially in combination with paclitaxel drugs. However, it can also be used alone, usually for one year. It is used once every three weeks.