According to the statistics, the incidence rate accounts for 7-10% of all kinds of malignant tumors in the whole body, which is the number one health killer threatening women. If we can correctly understand the factors of breast cancer development and actively control and treat it, the chance of successful cure of breast cancer will be another picture. 1. Mental depression and excessive tension: According to the survey, introversion, long-term mental depression and unhappy early life are the important factors leading to cancer. Young urban women face fierce competitive pressure and their spirits are in a state of stress and tension for a long time, leading to emotional instability and lack of peace. These mental factors together with bad life and work style cause further damage to breasts. 2, ionizing radiation: the breast is a more sensitive tissue to the carcinogenic activity of ionizing radiation. When young, the mammary gland mitotic activity stage is the most sensitive to the carcinogenic effect of ionizing radiation, and the effect of ionizing radiation has a cumulative nature, multiple small dose exposure and a large dose exposure to the same degree of risk, with dose-effect relationship. Among the survivors of the atomic bombing in Nagasaki, Japan, the proportion of breast cancer increased significantly, and those who had received chest radiotherapy during childhood and adolescence also had an increased chance of breast cancer when they grew up. 3, unhealthy lifestyle: some long-term office work of female white-collar sitting more than moving less, lack of exercise, less exposure to sunlight. Most professional women, due to their work, spend a lot of time with their bras tightly closed and rarely give their breast glands a break; some professional women are forced to live a single noble or dinky life due to the pressure of work or the pursuit of career success, without a family and without children. These factors are related to mastopathy. 4. Unhealthy eating habits: The incidence and mortality of breast cancer are strongly correlated with the amount of digested fat per capita. The high income of some company employees leads to a high standard of living, resulting in an unscientific and unhealthy “high-calorie, high-fat” diet, which leads to a much higher incidence of breast cancer. 5.Drugs: Some drugs such as antihypertensive drugs like reserpine, phenothiazole and steroids have the effect of increasing the incidence of breast cancer. Some health products, skin care products and cosmetics contain cancer-causing ingredients and should be used with special caution. In addition, harmful air, residual pesticides on vegetables and fruits all have different degrees of carcinogenic ingredients. 6. Hormones: Breast cancer is related to the imbalance of human endocrine balance. Among the various endocrine factors, the most important ones are estrogen and progesterone. Research results show that estrogen stimulates excessive proliferation of breast glandular epithelial cells, which is an important cause of breast cancer. The frequent use of hormone supplies and hormone replacement therapy for women during menopause can increase the risk of breast cancer. 7. Acidification of body tissue fluid: body cells are in acidic body fluid, which in turn forms a decrease in dissolved oxygen of normal body cells, resulting in a decrease in cellular activity and slowing down of metabolic cycle to 65% of normal value, normal cells cannot survive, but there are also cells that take active mutation without changing chromosomes, the phenotype of cells is changed and tumor traits are expressed, these cells expand rapidly, thus forming true tumor entities. In addition, there is also cancer of other tissues that occurs in the body due to acidification of the body, and due to the decline of body functions and acidification of body tissues, cancer cells take advantage of the situation and cause breast cancer. The causes of breast cancer are different for each woman, but it is important to note that early symptoms of breast cancer must be sought early, as leaving it to develop will only reduce the possibility of a successful cure.