The superficial location of breast tissue and few interfering factors make it very suitable for ultrasound examination. Moreover, the application of ultrasound examination of breast tissue is simple and easy, safe and non-invasive, non-radioactive, repeatable, and easily accepted by patients. Ultrasound examination is mainly applied to diseases such as lobular hyperplasia, inflammation, cysts, fibroids and breast cancer. Among them, it is mainly used to detect early breast cancer, as well as to examine whether there are enlarged lymph nodes in the axilla and supraclavicular area, to identify the benignity and malignancy of breast lumps and to track the development and evolution of lesions, providing a reliable scientific basis for clinical diagnosis and treatment. In recent years, the incidence of breast cancer in China is increasing year by year and now occupies the second place among female malignant tumors. Its treatment effect and prognosis depend on the early and late detection of lesions, therefore, early diagnosis of breast cancer is the key to improve the survival rate of patients. The use of ultrasonography for breast cancer screening has enabled many breast cancer patients to be diagnosed and treated at an early stage. And color ultrasound examination can improve the correct rate of judging the benignity and malignancy of breast lumps. With the improvement and enhancement of ultrasound imaging technology, especially the development of color Doppler ultrasound technology, the internal structure of breast tumor and the relationship between tumor and surrounding tissues can be more clearly displayed; the size, shape and edge of the lesion can be clearly shown; the number of blood vessels and the distribution of blood color in the tumor can be better observed; the color Doppler blood flow spectrum of benign and malignant tumors can be detected, thus This makes ultrasound an important and convenient advanced means to examine breast diseases. So what is the basis of ultrasound to determine the benignity and malignancy of breast lumps? Breast lump morphology: Breast cancer is a malignant tumor arising from the ductal epithelium and alveolar epithelium of the breast, most of which originate from the ductal epithelium of the breast. Therefore, the infiltrative border is the main feature of breast cancer, with the highest occurrence rate of crab foot, burr sign and marginal angle sign on ultrasound. Because of the irregular and swelling growth of breast cancer, the growth of the mass is often out of the normal tissue plane, resulting in an increase in the anterior-posterior diameter, and therefore the longitudinal-to-transverse ratio of the lesion is >1 (anterior-posterior diameter is larger than the transverse diameter). Second, the situation of supraclavicular and axillary lymph nodes: under our normal circumstances the lymph nodes in these two areas are not enlarged, and the texture of the lymph nodes is relatively soft. If we find a breast lump and at the same time find enlarged lymph nodes, and cannot find other diseases causing the enlarged lymph nodes, we should suspect that the breast lump may be malignant. Thirdly, the sound image of calcification within the lump: calcification has an important value for the diagnosis of breast cancer. Cancer cells are rich in calcium and phosphorus elements, and the cell metabolism is vigorous, aerobic and anaerobic glycolysis is more active than normal cells, and the biochemical process can easily have calcium salt deposition in the glandular alveoli and ducts. The calcification of breast cancer is characterized by pinpoint-like or mud-like microcalcifications, and is more frequently distributed in clusters or can be scattered. Due to the high resolution of ultrasound, it is easy to detect the calcification within the mass. IV. Blood flow in and around the lump: Breast cancer can stimulate the body to produce a tumor angiogenic factor to stimulate angiogenesis, forming a rich vascular network. These vessels are numerous, irregular, uneven in thickness, thin-walled, lacking in muscular layer, and prone to form arteriovenous fistulas. These features provide a pathological basis for the multi-flow nature of breast cancer and the accelerated blood flow within the tumor, which is manifested on the ultrasound by more blood colors in or around the mass, and sometimes the penetrating vessels, especially arterioles, can be found within the mass. In combination with the sonographic presentation, these features are of more clinical value. Experienced color ultrasonographers can improve the rate of judging the benignity and malignancy of breast masses by combining clinical features of the tumor (such as the presence of abnormal overflow from the nipple, whether there are orange peel-like changes in the skin on the surface of the tumor, and factors such as the hardness and activity of the mass on palpation). Although color Doppler ultrasound is valuable for accurate localization of microscopic lesions and tumors, and can provide clinical reference for benign and malignant lesions, ultrasound image diagnosis is non-specific, and many lesions are similar, and images of benign and malignant tumors are similar and crossed, which can easily lead to misdiagnosis or omission. Therefore, close clinical integration and comprehensive judgment are necessary to make a more correct diagnosis.