Sentinel lymph nodes are the first station lymph nodes that the primary tumor must pass through during the process of lymph node metastasis, and the number may be only one or more than one, as each patient’s physical condition is different. Sentinel lymph node biopsy is now widely used in the analysis of breast cancer, cervical cancer and vulvar cancer. When no tumor cells are found in the sentinel lymph nodes, it is more accurate to prove that the tumor has not yet undergone lymphatic metastasis. With the improvement of people’s health awareness and the popularization of early screening for breast cancer, most breast cancer patients do not show lymph node metastasis. If the sentinel lymph node pathological examination determines that there is no tumor metastasis, the patient can avoid axillary lymph node dissection, which can prevent it from leading to edema of the patient’s affected upper limb and improve the patient’s quality of life. Therefore, sentinel lymph node biopsy has been widely recognized in the analysis of early breast cancer. With more and more research, sentinel lymph node biopsy has a very broad application prospect in the clinic.