Diabetes mellitus is a group of metabolic syndromes characterized by chronic hyperglycemia. In 1997, the American Diabetes Association (ADA) divided diabetes into four categories: type 1 diabetes, type 2 diabetes, other types of diabetes, and gestational diabetes. Etiology: The etiology and pathogenesis of type 1 diabetes is mainly due to the lack of insulin secretion as a result of autoimmune inflammation of pancreatic islet B cells caused by viral infection and chemical infection in a susceptible population background leading to B cell destruction and functional impairment. Type 2 diabetes has significant genetic heterogeneity and is influenced by a variety of environmental factors, and its pathogenesis is related to insulin resistance and relative lack of insulin secretion, both of which are said to be inhomogeneous. Diagnostic criteria: 1. According to WHO (1999) standard, fasting blood glucose ≥7.0mmol/L, or random blood glucose ≥11.1mmol/L can be diagnosed as diabetes mellitus. 2.Fasting blood sugar 》6.1mmol/L, but oral 75% glucose tolerance test two-hour blood sugar ≥11.1mmol/L.