Ultrasound examination can be done to determine whether there is metastasis in the breast lymph nodes. Breast cancer lymph node metastasis is relatively more common. During ultrasound examination, it is necessary to check not only the condition of breast lumps but also the condition of lymph nodes around the breast, focusing on the condition of axillary lymph nodes, whether there are enlarged lymph nodes and whether the lymph node gates disappear, whether there are abnormal blood flow signals, and whether the lymph nodes are fused into clusters. If lymph nodes are found to be enlarged, lymph node gates disappear, fuse into clusters or have abnormal blood flow signals during the examination, it is considered to be tumor metastasis. If no lymph node enlargement is found during the examination or no tumor metastasis is judged, the anterior lymph node examination method can be used. During the surgery, a tracer, or contrast agent, is injected into the middle of the breast tumor to observe whether there is staining of the surrounding lymph nodes, which can judge whether there is tumor metastasis.