Breast cancer is one of the most common malignant tumors in women, with about 1.2 million women suffering from breast cancer and 500,000 dying from breast cancer worldwide every year. Although China is a low incidence area for breast cancer, the incidence rate has increased significantly in recent years, and it has become the first malignant tumor among women in some big cities such as Shanghai. The success of breast cancer treatment depends largely on the stage of the disease at the time of diagnosis, and the detection of an earlier stage of breast cancer is far more significant to patients than any current treatment options. 1997 American Cancer Society (ACS) established the promotion principles of early detection of breast cancer, which include: 18–39 years old: monthly breast self-examination and 3-yearly clinical physical examination. 40–49 years old Age 40–49: annual clinical checkup and mammogram, women at high risk should consult with their physicians about the need to start screening before age 40 and the interval between mammograms at age 40–49. Age 50+: annual clinical checkup and mammogram, monthly breast self-examination. For women in China, regular screening is recommended according to the following risk factors for breast cancer with reference to the promotion program: 1. family history of breast cancer; 2. previous history of benign breast tumors; 3. not having children; 4. first full-term pregnancy older than 30 years; 5. age of first menstruation less than 12 years or menopause after 55 years; 6. excessive consumption of animal fat and overweight after menopause; 7. long-term oral or injected estrogen. or injections of estrogen. Numerous studies have confirmed that mammography is currently the most effective method for early detection of breast cancer. The direct signs of breast cancer on X-ray mainly include mass nodules and microcalcifications. Malignant mass shadows are often irregular, with burred edges and higher density than the surrounding glands. It has been found that about half of the breast cancers that are not detected on breast screening are detected due to the presence of microcalcifications; 70% of the detection of intraductal breast cancer is attributed to the detection of microcalcifications on X-ray. However, not all microcalcifications on mammograms are malignant. Calcified spots in breast cancer usually appear as mucoid, in clusters or in a segmental distribution along the ducts. X-rays are inherently harmful and may induce breast cancer, but studies have found that a radiation dose of less than 1 cGY per year does not affect women over the age of 40. Since the breast gland of young women is sensitive to radiation and the breast tissue is dense at this time, it is not easy to detect lesions, so it is generally considered inappropriate for women under the age of 35 to undergo mammography. Since the breast gland tissue itself changes with the menstrual cycle, the best time for mammography is 1 – 2 weeks after menstruation. Ultrasound of the breast can clearly show all layers of structures in the breast and is a valuable imaging method for the diagnosis of breast diseases. Ultrasound is more sensitive to cystic lesions and can clearly distinguish between cystic and solid masses and detect breast tumors in cystic hyperplastic lesions; it is real-time and can dynamically observe the elasticity and mobility of lesions and can observe color Doppler blood flow; it can confirm lesions that are not clinically palpable or not detected by X-ray and can be feasible for ultrasound-guided biopsy and preoperative localization; it can show axillary lymph nodes; it helps to evaluate Ultrasound is non-radioactive and is the preferred method of examination for breast lesions in young or pregnant and lactating women, but its diagnostic accuracy depends largely on the equipment used and the personal experience of the examining physician. In addition to imaging, self-examination of the breast and regular clinical checkups are also one of the effective methods for early detection of breast cancer. Therefore, it is recommended that women aged 18 – 39 years old adhere to regular breast self-examinations, clinical physical examinations and breast ultrasound examinations according to the above guidelines; women over 39 years old should undergo annual mammography examinations on top of these examinations, which are especially necessary for breast cancer screening and early detection. Primary prevention will play a direct and critical role in the control of breast cancer, and clinicians or related professionals should actively promote the above guidelines to patients with breast disease who come to the clinic or their family members, and spread them as an effective method of controlling breast cancer. For women with any abnormalities found during regular examinations, including clinical findings of lumps or imaging abnormalities, further pathological examinations should be taken promptly to clarify the diagnosis.