Diabetes mellitus type 1 and type 2 are the two common types of diabetes mellitus typing. The causes are different and the severity is not differentiated by typing, but is judged by the degree of glycemic control achieved and the acute and chronic complications. Type 1 diabetes is mostly autoimmune diabetes, the cause of which is the absolute lack of pancreatic function, often congenital, while the cause of type 2 diabetes is insulin resistance and insufficient insulin secretion, although there is a genetic tendency, but often caused by acquired factors, and no matter which type of diabetes, once discovered, should go to a regular medical institution as soon as possible, under the guidance of a specialist In addition, they should do long-term regular blood glucose monitoring, healthy diet and life, moderate exercise, quit bad habits, control blood glucose long-term standard, prevent and delay the occurrence of complications, because the complications of diabetes are the important factors that lead to the seriousness of diabetes. Therefore, it is not possible to judge which is serious from the type of diabetes alone. Both diabetes type 1 and type 2 are not serious as long as the blood sugar is well controlled and serious complications are prevented.