Diabetes mellitus is mainly categorized into type 1 diabetes mellitus, type 2 diabetes mellitus, special type of diabetes mellitus and gestational diabetes mellitus. Typical symptoms are three more and one less: drinking more, urinating more, eating more and losing weight. However, there are differences in the symptoms of different types of diabetes. 1.1 type 1 diabetes: often in adolescents, the onset of the disease is more acute, the symptoms are obvious, manifested in the typical three more and one less symptom: more drinking, more urination, more food, weight loss, serious coma can occur, easy to occur ketoacidosis. 2. Type 2 diabetes mellitus: the disease often starts after 40 years old, most of them have insidious onset and relatively mild symptoms, more than half of them do not have any symptoms; a lot of patients consult the doctor because of the symptoms of chronic complications, such as retinopathy leading to vision loss or even blindness, peripheral neuropathy leading to numbness of hands and feet, and so on. 3. Special type of diabetes mellitus: this includes diabetes mellitus caused by genetic defects in islet cell function, genetic defects in insulin action, and pancreatic exocrine diseases. There can also be symptoms of wasting or even coma. 4. Gestational diabetes mellitus: It is an abnormality of glucose metabolism that occurs during pregnancy, usually in the middle or the end of pregnancy, and the blood glucose usually returns to normal after delivery, but the risk of diabetes mellitus increases significantly in the future. Some patients may be asymptomatic, found during pregnancy tests, and some may have excessive drinking, urination and eating. If elevated blood glucose is found, timely consultation should be made to further clarify the diagnosis and typing, and long-term standardized treatment should be carried out under the guidance of doctors.