Diabetes mellitus is mainly divided into type 1 diabetes mellitus, type 2 diabetes mellitus, special type of diabetes mellitus and gestational diabetes mellitus, to distinguish between type 1 diabetes mellitus, type 2 diabetes mellitus need to look at the following points: 1, the age of onset and clinical performance, type 1 diabetes mellitus occurs in children and adolescents, acute onset of the disease, with the typical “three more and one less” symptoms, easy to occur diabetes Type 2 diabetes occurs in people older than 40 years old, can have a family history of diabetic ketoacidosis can also occur in infections and other triggers. 2, pancreatic β-cell function test, type 1 diabetes mellitus manifested as pancreatic β-cell failure, insulin and C-peptide release test shows a low curve, type 2 diabetes mellitus is manifested as delayed insulin secretion peak. 3, related antibodies, type 1 diabetes mellitus have insulin cell antibodies, type 1 diabetes mellitus have insulin cell antibodies, type 1 diabetes mellitus have insulin cell antibodies. Type 1 diabetes mellitus is positive for islet cell antibodies, insulin antibodies and glutamic acid decarboxylase antibodies, while type 2 diabetes mellitus is negative for the above mentioned antibodies.4. In terms of treatment, type 1 diabetes mellitus is mainly characterized by insulin deficiency, which needs to rely on insulin treatment, while type 2 diabetes mellitus is characterized by insulin deficiency as well as insulin resistance, and it can be treated by either oral medication or insulin therapy. The above points, and the relevant antibody positivity is the gold standard for distinguishing between type 1 and type 2 diabetes.