Estrogen is a very important sex hormone in women. It is mainly produced by the female ovaries and has biological effects by binding with the estrogen receptor (ER) in vivo. In recent years, studies have found that estrogen and its receptors can not only promote the development of female reproductive organs, but also have the role of central nervous system protection, anti-osteoporosis, tumor inhibition and improvement of metabolic diseases. This article reviews and summarizes the research progress of estrogen and its receptors in female diseases and the application of phytoestrogens, in order to provide evidence for the clinical application of estrogen and the development of new drugs.