Breast cancer is not an incurable disease, but the key is early detection and early treatment. Over the years, clinical practice has confirmed that, for most cancers, it is difficult to improve the cure rate by improving the treatment methods alone. The 10-year survival rate of early stage breast cancer can generally reach over 90% after surgery. Early detection and early treatment is the effective way to improve the survival rate of breast cancer. In the natural course of breast cancer growth, preclinical stage accounts for about 2/3 of the whole process, but early stage cancer may not always form obvious lumps, so early stage cancer is seldom detected. Therefore, it is important to pay attention to breast self-examination and seek medical attention in time when abnormalities are detected, and to see a breast specialist once a year for a physical examination. There are many predisposing factors for breast cancer, the common ones are as follows: (1) family history of breast cancer, especially whether the mother and sister of the subject have suffered from this disease; (2) early menarche (less than 12 years old) or late menopause (more than 50 years old); (3) childbirth at the end of 40 years old or older; (4) cancer in one breast and the opposite breast is also a predisposing area, etc. All these factors should be taken into consideration. Anyone with these factors should be considered as breast cancer-prone and should be a key target for examination. (1) Nipple overflow, especially bloody overflow, is more likely to coexist with breast cancer, especially when it occurs in women over 50 years old, about half of them may be malignant. (2) Restricted thickening of the breast gland, which is a very common but underappreciated sign in clinical practice. This condition is physiological if it occurs in non-menopausal women, especially when there is some size change with the menstrual cycle. If the thickened tissue persists for a long time, independent of the menstrual cycle, or if it becomes increasingly thick and extensive, especially in postmenopausal women, it must be taken seriously. (3) Paget’s disease should be considered when papillary erosion is not treated repeatedly with local therapy, and a high rate of positive cytologic smears should be made in time for diagnosis. (4) Breast pain, in premenopausal women, is mostly physiological, especially when the degree of pain varies with the menstrual cycle and is mild or severe. If the pain is limited, has a fixed location, is not related to the menstrual cycle or is in postmenopausal women, the cause should be identified. (5) Unexplained edema of the areola skin, nipple retraction and limited depression of the breast skin should be carefully investigated. (6) Lymph node enlargement in the axilla and neck Breast cancer is prone to ipsilateral axillary and neck lymph node metastasis, so when local lymph node enlargement is found, immediate medical consultation should be sought. In conclusion, early detection and early treatment are undoubtedly the development direction of breast cancer prevention and treatment. What is urgent now is to popularize the knowledge of early detection and diagnosis of breast cancer and to widely carry out breast cancer screening and women’s self-examination of breast, so as to achieve the goal of improving the survival rate and reducing the death rate as soon as possible.