In addition to the physical examination by a doctor, i.e. palpation, the breast is sometimes examined with the help of imaging tests. The most commonly used are color ultrasound and mammogram. What are the functions of color ultrasound and mammography? Mammography is a widely used imaging method for screening and diagnosis of breast disease, which is essentially an X-ray camera of the breast. Breasts are soft tissues with different densities of skin, glands, and fat, and the use of low-energy rays for mammography can clearly show the glands, ducts, fibrous septa, skin, subcutaneous tissue, vascular structures, and diseased lumps and subtle calcifications of the breast, and this method of examination, called “Mammography”, is rapidly gaining clinical acceptance. For women over 50 years of age, annual bilateral mammograms are recommended. For women with high risk factors for breast cancer, annual mammograms can be started between the ages of 40 and 49. Mammography is not recommended as a routine screening test for women under the age of 40 because most of the breast glands in younger women are denser, the resolution of the mammogram is reduced, and the glandular tissue in younger women is more sensitive to radiation. Mammography is often the preferred modality for older patients with loose breast tissue, as it shows up very clearly in this group. Another specialty of the mammogram is the diagnosis of microcalcifications in the breast, which cannot be replaced by other diagnostic methods. Besides, ultrasound, breast ultrasound is to transmit ultrasound into the body and propagate it in the tissues. When ultrasound passes through different kinds of tissues, it will produce reflections and refractions with different amplitudes, and the acoustic image can be obtained by processing these echoes, and the nature of the lesion can be judged according to the size, shape, contour boundaries, type of echoes, the internal condition of the echoes, and attenuation at the back of the lesion shown in the acoustic image. Ultrasound examination of the breast can distinguish between cystic and parenchymal lesions, and with the operation of an experienced doctor, it is often possible to find a mass of 25px or even smaller, and through the analysis of the characteristics of the mass on the ultrasound image and the blood flow situation, the rate of early detection of breast cancer can be maximized. Breast ultrasound diagnosis is more meaningful for young people and people with dense breast tissue. We do not routinely perform mammography for the former because they need to receive a certain amount of radiation; and for the latter, the diagnostic rate of mammography is significantly reduced due to the high density of the tissue, so ultrasound is also needed to make up for this. For us Chinese women, dense gland types are more common, so breast ultrasound is particularly important. Summarizing the advantages and disadvantages of the two, we find that: Mammography has a higher diagnostic efficacy in older patients, patients with loose breasts, and has a unique advantage in the diagnosis of microcalcifications. The disadvantage is that there is a certain amount of radiation, and the examination of the breast to withstand a certain amount of pressure, uncomfortable; ultrasound is the preferred diagnostic modality for the young or dense type of breast, with the advantages of simplicity, inexpensive, non-invasive, relatively comfortable. Therefore, making full use of these two means of examination can maximize the level of diagnosis of breast diseases and achieve early detection and treatment of diseases.