Breast cancer is one of the most common malignant tumors in women. Its incidence rate accounts for 7%-10% of all kinds of malignant tumors in China, second only to cervical cancer, but in recent years it has a tendency to exceed cervical cancer and is on the rise year by year. Some major cities report that breast cancer is the first malignant tumor in women. The early manifestation of breast cancer is a painless lump in the affected breast, which is hard, not smooth on the surface, not clearly demarcated from the surrounding tissues, and not easily pushed in the breast. As the lump increases in size and invades the surrounding tissues, it may cause: breast surface elevation; skin depression on the surface of the tumor, i.e. “dimple sign”; nipple invagination and nipple position change; local skin lymph node edema and many dotted depressions in the hair follicles, forming “orange peel-like” changes. “When the lump of cancer is large, it is obviously protruding locally and several small nodules may appear. Lymph node metastasis of breast cancer is commonly in the axillary lymph nodes of the affected side. The enlarged lymph nodes are first scattered, hard, painless, and can be pushed, and then increase in number and adhere to the skin or deep tissue in severe cases. In advanced stages, both supraclavicular and contralateral axillary lymph nodes may be enlarged. When metastasis to lung, bone and liver, corresponding symptoms may appear. Lung metastasis may cause chest pain and shortness of breath; bone metastasis may cause local pain; liver metastasis may cause hepatomegaly and jaundice, etc. Surgery is one of the main treatments for breast cancer, supplemented by chemotherapy, endocrine therapy, radiation therapy, and recently, biological therapy. Surgery is the first choice for patients whose lesions are still confined to local and regional lymph nodes. Surgery is contraindicated for patients with distant metastases, poor general condition, serious diseases in major organs, and those who are too old and frail to tolerate surgery. The cause of breast cancer is still unknown, and it is difficult to propose a definite etiological prevention (primary prevention). However, the improvement of 5-year survival rate in surgical treatment of breast cancer in the past 10 years or so is attributed firstly to early detection and diagnosis, and secondly to the continuous improvement of postoperative comprehensive treatment. Therefore, paying attention to the early detection of breast cancer (secondary prevention) will improve the survival rate of breast cancer. Breast cancer is a superficial tumor and easy to detect. In order to detect breast cancer at an early stage, medical personnel must strengthen health education and screening, conduct regular screening for women over 30 years old, detect cases by screening, and guide monthly breast self-examination, which will help early diagnosis and early treatment of breast cancer and help improve the survival rate of breast cancer. The screening of breast cancer includes detailed history taking, clinical examination, mammogram, infrared thermogram, ultrasonography, nipple overflow cytology, biopsy and follow-up after the screening.