Advantages of ultrasound examination: painless and non-invasive, no radiological damage, and can be performed repeatedly. Ultrasound examination can be performed at any age, during pregnancy, lactation or due to trauma or inflammation, so that the location, shape, structure and surrounding tissues of the lesion can be well displayed. 1.Sonographic features of breast cancer The breast shows an irregularly shaped solid mass with a “crab foot” border, no or incomplete envelope, mostly hypoechoic with uneven distribution of echogenicity, a few of them are strong or isoechoic. If there are lymph node metastases, the axilla may show single or multiple round hypoechoic homogeneous nodule-like masses. Color multispectral can see stellate or striped color flow inside and around the mass, and arterial spectrum can be seen, usually with a high resistance index of 0.75-0.89. 2. Sonographic features of breast fibroadenoma The mass is mostly round or oval in shape, with regular and clear borders, mostly with strong echogenicity of the envelope, uniform hypoechogenicity inside the mass, often with lateral echogenicity and some posterior enhancement effects, and no enlarged lymph nodes in the ipsilateral axilla. There is no enlarged lymph node in the ipsilateral axilla. The color multispectral echo shows less colored blood flow within and around the mass, and the resistance index is usually <0.70. 3. Sonographic features of breast cysts An oval or rounded anechoic breast gland with clear borders and a homogeneous fine-dotted hypoechoic or anechoic interior with posterior echogenic enhancement and no ipsilateral axillary lymph node enlargement. 4. Sonographic features of breast adenomatous hyperplasia Nodules of variable size, round or oval in the breast gland, with no envelope and poorly defined borders, slightly hypoechoic and relatively uniformly distributed internal echogenicity, no posterior echogenicity, no ipsilateral lymph node enlargement, and no significant color flow as shown by color multispectral. 5.Sonographic features of breast abscess The ultrasound performance of breast abscess is a hypoechoic mass in the early stage with unclear boundary, irregular shape with the aggravation of the disease, irregular liquid dark area and flocculent echogenicity when abscess formation is seen.