The need for chemotherapy for breast cancer is determined by the size of the breast cancer, the immunophenotyping of the tumor, and the status of the axillary lymph nodes. Chemotherapy can be divided into neoadjuvant chemotherapy, adjuvant chemotherapy and palliative chemotherapy. Neoadjuvant chemotherapy is the chemotherapy before surgery. It can be used for some patients with larger tumors. It can reduce the stage, turn some inoperable patients into operable and verify the effect of chemotherapy drugs. If complete pathological remission is achieved after chemotherapy, its long-term survival rate will be better than those who are not in complete remission. Adjuvant chemotherapy i.e. chemotherapy after surgery. Long-term clinical follow-up results confirm that chemotherapy for breast cancer can reduce the mortality rate by 30% and the recurrence rate by 50%. The so-called relief chemotherapy is chemotherapy for recurrent and metastatic breast cancer. It is a process of repeated treatment. Therefore, the initial treatment for breast cancer is very important and is a comprehensive treatment process; otherwise, once it recurs, it is a lifelong treatment. With the progress of science and technology, the selection of breast cancer chemotherapy cases based on gene sequencing will be further precise, which is the direction of the near future.