Breast cancer is prone to axillary lymph node metastasis; therefore, axillary lymph node dissection for breast cancer is one of the necessary means for breast cancer surgery. There are two methods of axillary lymph node dissection for breast cancer: First, the dissection of the sentinel lymph nodes. Second, standard axillary lymph node dissection, which can be based on the results of the sentinel lymph node biopsy to decide whether axillary lymph node dissection is needed. If the sentinel lymph node biopsy is positive, then axillary lymph node dissection needs to be continued. If the axillary lymph node biopsy is negative, axillary lymph node dissection may be waived. Because the sentinel lymph node is the first station lymph node where breast cancer metastasizes, if the sentinel lymph node is negative, the possibility of metastasis in the axillary lymph node is low and axillary lymph node dissection can be avoided because lymph node dissection can bring many postoperative complications, such as edema of the upper limbs, stiffness of the axilla, etc.