Women are susceptible to breast cancer, the causes of which are caused by a variety of factors involving diet, fertility and hormonal imbalance, as follows: 1, reproductive history, some women with early menstrual periods, no or fewer children, and women of advanced age who give birth at the beginning of pregnancy are prone to breast cancer; 2, exogenous hormones, oral contraceptives and menopausal substitution drugs, which can mildly increase the risk of breast cancer; 3, nutrition, and the intake of large amounts of vegetables, fruits have the potential to reduce the risk of breast cancer. And obese body type reflects the imbalance between high calorie intake and consumption, which is a risk factor for postmenopausal breast cancer; 4. Alcohol has been considered to make breast cancer risk mildly increase; 5. Smoking, pharyngeal grass is considered to be a protective factor that can resist estrogen; 6. Body weight, if the postmenopausal women are overweight, it can increase the risk of breast cancer; 7. Exercise, after menopause, start some appropriate Exercise, after menopause, starting some proper exercise is good for controlling body weight and reducing the risk of breast cancer; 8, endogenous hormones, research shows that androgen, estrogen and progesterone play an important role in the occurrence and development of breast cancer. When the ovaries stop synthesizing estrogen and progesterone, as well as when the production of androgens gradually decreases, the incidence of premenopausal compared to postmenopausal breast cancer increases linearly with age; 9. Special exposures, special environmental exposures related to breast cancer are also associated with a certain degree of risk, for example, accepting tuberculosis treatment and being exposed to the immune-surveillance effect of tuberculosis are both associated with the development of breast cancer. Therefore, there are more causes of breast cancer, women are prone to breast cancer, it is recommended that patients must avoid adverse factors to prevent the disease.