Breast cancer has become a major public health problem in our society today. The global breast cancer mortality rate has shown a decreasing trend since the 1990s; the reasons for this are, firstly, the screening of breast cancer, which has increased the proportion of early cases, and secondly, the development of comprehensive breast cancer treatment, which has improved the efficacy. Breast cancer has become one of the solid tumors with the best curative effect. Nowadays, we all attach great importance to regular medical check-ups in hospitals, on the other hand, it is also important to develop a good habit of self-examination. The best time for breast self-examination should be about 7 days after menstruation, because at this time the breast is softer and easier to find lesions. Generally, it is convenient and feasible to perform breast self-examination in the following three situations: (1) Checking your breasts in the shower, especially before the shower gel is washed away and your hands are easily moved on the wet skin. Gently move your flat hand (i.e., fingertip position) over each part of your breast. Examine the left breast with the right hand and the right breast with the left hand to check for lumps, hard nodes or thickening. (2) To examine in front of the mirror, lower both hands to the sides of the body in front of the mirror, then slowly raise both upper limbs above the head and observe the morphological changes in the breasts, including the contours of the breasts, the presence of swollen parts, and the presence of slightly concave skin or retraction of the nipples. Next, cross your arms and observe whether the bilateral breasts are symmetrical. (3) To examine while lying down, place a pillow or soft object under the shoulder blade on the side of the breast being examined while lying down. Then place the hand on the same side behind the head so that the tissue of the breast is more evenly apportioned across the chest. The flattened hand is pressed lightly against the skin and the examination is moved gradually, centered on the nipple. The examination begins at the outer top of the breast, clockwise for the right breast and counterclockwise for the left breast; starting at the periphery of the breast and gradually moving inward to the nipple. Finally, the nipple is gently squeezed between the thumb and index finger to observe whether there is nipple discharge. If there is overflow, observe whether it is clarified or cloudy, yellowish, milky or bloody. Once an abnormality is detected, medical attention should be sought immediately.