Polycystic ovary syndrome is closely related to diabetes. Patients with polycystic ovary syndrome are prone to insulin resistance, and patients with insulin resistance are prone to diabetes. Polycystic ovary syndrome is associated with genetics and obesity, and when obesity occurs in female patients it can lead to insulin resistance and hyperinsulinemia. Hyperinsulinemia stimulates ovarian hyperplasia and increased production of androgens, leading to polycystic ovary syndrome. Therefore, patients with polycystic ovary syndrome tend to present with obesity, menstrual disorders, anovulation, infertility, elevated androgen levels, abnormal glucose metabolism, and even diabetes mellitus. Polycystic ovary syndrome and diabetes mellitus are closely related, and they share a common pathogenic basis, which is obesity and insulin resistance caused by obesity. When insulin resistance is severe, the hypoglycemic effect of insulin is reduced and abnormal glucose metabolism and even diabetes will occur.