Breast cancer is one of the most common tumors in women. Its incidence has been gradually increasing worldwide for half a century, and the age of onset is tending to be younger. The prognosis of breast cancer patients directly depends on the stage of the lesion at which treatment is started. Early detection, early treatment and active rehabilitation are important aspects to improve the quality of survival and reduce the death rate. Although there are a lot of advanced aids for breast examination in recent years, and there is no denying that some breast lesions can be detected by chance such as dressing or showering, regular monthly breast self-examination, as an easy-to-teach, simple and economical examination method, does play a certain role in early detection of breast cancer, but the key is how to master the application scientifically. In order to eliminate the possible negative effects of breast self-examination, the following aspects should be grasped. Breast self-examination can be done before going to bed or before taking a bath. First take off your coat and stand in front of a mirror with your arms hanging down naturally, first carefully observe whether the shape and size of both breasts are symmetrical, whether the nipples are at the same level, whether the nipples are sunken in, and whether the side is to one side. It is important to compare the appearance with the previous examination to see if there are any changes. Then look for any localized elevation or depression of the breast, and pay particular attention to whether there is any “orange peel-like” unsmooth change on the surface of the breast, and whether there is any overflow of fluid or blood from the nipple. If no abnormality is found, both arms should be raised or both arms crossed, and the above observations should be repeated. 2, “touch” diagnosis Take a supine position, place a soft pillow on the back, make the chest lift, the upper arm of the examination side to the head, the palm of the hand can be placed under the pillow, in order to fully display the breast, easy to touch. Use the right hand to examine the left side and the left hand to examine the right breast. Touch the index, middle and ring fingers together, straighten them, and touch gently with the belly of each finger and the palm side, but do not press heavily. You can follow the inner upper, outer upper, outer lower, inner lower order of the breast, and finally massage the deep tissue under the areola. After touching both sides of the breast then feel the armpits on each side for enlarged lymph nodes. Finally, squeeze the areola with your thumb and forefinger to see if there is any fluid spillage from the nipple. When touching your breasts, do not use your hands to grab and squeeze them, so as not to take the normal breast tissue as breast lumps. A normal breast feels soft and elastic to the touch, with no lumps or hard knots to the touch. Often people check incorrectly and use their fingers to grab and pinch the breast, resulting in the breast lobe being mistaken for a lump, leading to mental tension. 3, selected time Breast self-examination does not have to be too frequent, women over 30 years old once a month can be. The best time to do this is 7-10 days after menstruation. Because the breast is affected by endocrine changes with the menstrual cycle, a few days after menstruation breast tissue is relatively thin, easy to check. It is important to prevent the examination on different days of the menstrual cycle so as not to affect the results due to the physiological changes of the breast. 4, with other examinations Self-examination process, if found on both sides of the breast size, position asymmetry, often suggest the existence of lesions on the larger side of the possibility, if the position of the height of the different, should be looking for the cause. Once a “dimple”-like skin depression appears on the breast, it is often an early manifestation of breast cancer, mostly due to the proliferation of tissues around the tumor, which pulls the skin in the direction of the tumor. If one side of the nipple is displaced or declined, or if the skin on the surface of the breast appears “orange peel-like”, it may be a sign of early breast cancer. If the nipple is sunken recently, it is often an important feature of central breast cancer. In addition, nipple overflow during non-pregnancy and breastfeeding periods often indicates a certain pathological state. In these cases, further examination should be performed at a regular hospital in order to determine the cause of various abnormal manifestations and the nature of the overflow and lump. Those who are able to do so can undergo annual mammograms and regular breast examinations. Finally, women should be reminded that even if they do find lumps in their breasts, there is no need to be afraid, because lumps are not equivalent to tumors, but may also be chronic inflammation, breast hyperplasia and other diseases, so they should go to a regular hospital for further examination as soon as possible after discovery.