Ultrasound of the breast is becoming more and more popular and is being performed in hospitals all over the world. Nowadays, women are more aware of health care and are no longer unfamiliar with “B” ultrasound. Many patients often ask what the “B” ultrasound terminology is when they visit the clinic or consult online, I think it is good to know some of the principles of “B” ultrasound and some common sense. Instruments and methods: Breast ultrasound examination generally uses color Doppler ultrasound high-frequency probe 7.5-13Mhz (megahertz), no special preparation is required before the examination, and it is best not to squeeze out the liquid before the examination if you have nipple overflow. The patient is placed in a supine position and the probe is placed directly on the breast surface, and the nipple and the four quadrants of upper outer, lower outer, upper inner and lower inner as well as the axilla are scanned comprehensively. The gray scale, or gray level, is displayed on the screen and is transmuted from high to low amplitude to black, gray, or white. The darker the color represents the higher the amplitude, the stronger the performance echo, i.e., the brighter the area. The lighter the color represents the lower the amplitude, the lower the performance echo, i.e. dark area. 1, cystic hyperplasia of breast sonogram performance glandular thickening, structural disorder, between the glands can be seen in the size of the echoless reflection area, ranging in volume from a few millimeters to 1-2 cm, very few can be larger. The cystic cavities are round or oblate in shape with clear and regular borders, while very small cystic cavities without obvious borders are mixed in the hyperplastic glands, and the cystic cavities can be scattered and multiple, or fused with each other in a reticular pattern. 2.Breast cyst sonogram performance The boundary of the mass is clear, the edge is smooth and neat, the cross-section is round or oval, and there is no echo reflection inside, sparse weak light drift is seen in larger cysts, and the posterior echogenicity is obviously enhanced. 3.Fibroadenoma of breast The tumor has moderate or low echogenic reflection and uniform distribution of echogenic dots. When fibrous tissue is the main component, the echogenic dots are enhanced and rough, and some cysts may have large or coarse speckled calcified spots. Most of the tumors are round or oval in shape, and a few are lobulated or flattened. The envelope of the tumor is intact, and in rare cases, the envelope is blurred. The posterior echogenicity of the tumor is not attenuated or slightly enhanced, and lateral acoustic shadow is visible. 4.Breast cancer Breast lump is not smooth at the edges, and the peripheral echogenicity is rough, and can be seen as small serrated extensions to surrounding tissues in a mosaic shape without obvious envelope. The posterior echogenicity of malignant tumor can be in the form of attenuation, non-attenuation, enhancement and lateral acoustic shadow, which is mainly due to the different tissue structure, acoustic impedance difference and the degree of absorption of acoustic wave in the tumor. Advantages of breast ultrasound 1. Non-hazardous. It is more suitable for the examination of young women, especially pregnant and lactating women, and it is more convenient to conduct screening and follow-up. 2.Identify the physical nature of the tumor. It is of great value to identify cystic or solid breast tumors, and ultrasound can detect cysts of 2mm. 3.Ultrasound can clearly show the anatomical level of the breast and the subtle lesions, thus giving a clear localization of the lesions. 4.Ultrasound can clearly show whether there are enlarged lymph nodes in the axilla and supraclavicular area, and can also characterize whether there is metastasis, mainly depending on whether there is a lymphatic gate, whether the medullary structure is destroyed, and the richness of blood flow. Especially for obese patients, when clinical diagnosis is difficult, ultrasound can provide the size and location of enlarged lymph nodes. Problems: 1. It is not clear for very small fine calcifications. 2.It is still difficult to differentiate between inflammatory breast masses and inflammatory breast cancer. High-frequency ultrasound examination of the breast has the advantages of being economical, simple, painless, non-invasive, and easily accepted by patients. As long as it is used properly, the examination of breast diseases can complement each other with X-ray mammography and can be used as the main means of early diagnosis of breast tumors.