Breasts with one large and one small size are not necessarily caused by cancer, but should be examined, the most common choice is color ultrasonography of the breast, which is relatively inexpensive and has no radiation. Many patients are due to congenital developmental abnormality, the size of bilateral breast glands is not consistent, and some patients even have asymmetric nipples. If there is no obvious space-occupying change in the breast glands in the ultrasound examination, there is no need for any special treatment or therapy. If the ultrasound found that there are obvious lumps and irregular changes in the breast gland, it is also necessary to further combine with the molybdenum target photography examination, not except for malignant tumors, and malignant tumors occurring in the breast under the imaging will be manifested as obvious feeder blood vessels, the burr sign or lobular changes, and the examination will also be manifested as the abnormalities of the breast skin, nipple overflow, localized concavity, and similar to the dimple sign changes.