The difference between type 1 diabetes and type 2 diabetes lies in the age of onset, urgency of onset, severity of symptoms, body weight, tendency to ketoacidosis, and dependence on exogenous insulin. 1. Type 1 diabetes mellitus usually develops at a younger age, most of the onset is more rapid, the symptoms are more obvious, the body weight is usually normal or thin, and there is a tendency of spontaneous diabetic ketoacidosis. Most patients with type 1 diabetes require insulin therapy in the early stages of the disease. 2. Type 2 diabetes mellitus is most common in adults, often starting after the age of 40; most of them have insidious onset and relatively mild symptoms. There is often a family history of the disease. Diabetic ketoacidosis rarely occurs spontaneously. Clinically, it occurs simultaneously or sequentially with obesity. Most of the type 2 diabetes mellitus by lifestyle intervention and oral hypoglycemic drugs can make blood glucose control standard, can not use insulin treatment. It is recommended that diabetic patients be typed and treated under the guidance of a physician.