Abstract:Vitamin D has a potential role in many extraskeletal diseases, including tumors, autoimmune diseases, cardiovascular disease, diabetes, and obesity. Vitamin D is a prohormone that needs to be metabolized into bioactive products and bind to its homologous nuclear receptor ［vitamin D receptor(VDR)］ to regulate different physiological processes. VDR exists in the reproductive system, such as uterus, ovary and other tissues. Recent studies have found that vitamin D deficiency is associated with polycystic ovary syndrome(PCOS). PCOS is often accompanied by infertility, metabolic dysfunction such as insulin resistance and dyslipidemia. Vitamin D level is associated with follicular dysplasia, metabolic disorders, cardiovascular disease and mental health in PCOS patients.Supplementation of vitamin D may improve insulin resistance, hyperandrogenemia and obesity caused by PCOS. This paper briefly reviews the research progress on the relationship between vitamin D and PCOS, explores the possible mechanism of vitamin D deficiency in PCOS patients, and provides ideas for the clinical treatment of PCOS.