Due to the increasing risk factors in life,the incidence and mortality of breast cancer continue to increase.This is not only reflected in female patients,the incidence of breast cancer is slowly increasing in men.It has been shown that genetic factors,hormone levels,breast diseases,bad living habits,some occupational factors and psychological factors are the main risk factors affecting the onset of breast cancer.Because more than 80% of patients with positive estrogen receptor expression in breast cancer,the most effective treatment for these patients is endocrine therapy.This article summarizes the risk factors for the development of breast cancer and its mechanisms and drugs for endocrine therapy.