The purpose of breast cancer surgery to clear the ipsilateral axillary lymph nodes is to achieve radical treatment of the tumor, that is, to completely remove all the areas where the tumor may spread and metastasize. In clinical practice, the most common metastasis of breast cancer is lymphatic metastasis and hematogenous metastasis. Once hematogenous metastasis occurs, it is easy to be found in distant tissues or organs, such as liver and lung. At this time, if metastatic malignant tumors appear in distant tissues and organs, the chance of radical surgical resection is usually lost. If lymph node metastasis occurs in the axilla alone, after radical resection and postoperative comprehensive treatment, most patients can achieve a better treatment result, that is, clinical cure. The most common route of lymphatic metastasis in breast cancer is mainly the ipsilateral axillary lymph nodes. Therefore, for breast cancer, usually the unilateral breast should be removed, and if there is cancer metastasis in the ipsilateral axillary lymph node, it needs to be completely removed so as to achieve complete cure of the tumor.