Diabetes is a very common disease of the endocrine system and has a tendency to run in families. As material living conditions improve, the incidence of diabetes is gradually increasing. The diagnosis of diabetes first has clinical manifestations which are also known as three more and one less: eating more, drinking more, urinating more and losing weight gradually. At this time, the possibility of diabetes should be highly suspected, and blood glucose, including fasting blood glucose and 2 hours after meal, should be monitored. If the fasting blood glucose is more than 6.1mmol/L or the 2 hours postprandial blood glucose is more than 11.1mmol/L, the diagnosis of diabetes mellitus is established. Further examination of the liver, kidney, retina and cardiovascular system is needed to assess whether there is any damage to the target organs of diabetes, that is, whether there are any complications, and to give corresponding treatment. Oral hypoglycemic drugs or insulin can be used. At the same time, attention should be paid to the diabetic diet, and after a comprehensive treatment, diabetes can be effectively controlled.