The timing of gastric diversion surgery can have a direct impact on the outcome of treatment. Studies have found that the longer the patient has had the disease and the older he/she is, the less likely he/she is to recover, so early surgical intervention is also quite important for the efficacy. Indications for gastric diversion surgery: 1. meeting the diagnostic criteria of type 2 diabetes; 2. islet function in the compensatory phase (plasma insulin level > normal value); 3. history of diabetes not more than fifteen years, the islets still have some residual function, more than fifteen years islet function is very poor, the effect of surgery is poor at this time, often after surgery can not completely stop insulin; 4. no serious complications; 5. history of diabetes less than 15 years or age less than 70 years. 5. History of diabetes is less than 15 years or age is less than 70 years. Contraindications to gastric diversion surgery: 1, advanced diabetes mellitus, islet failure; 2, serious organic disease, can not tolerate surgery; 3, gastrointestinal tract dysfunction, moderate to severe diabetic gastroparesis; 4, history of diabetes mellitus greater than 15 years or age greater than 70 years old, suffering from serious complications; 5, autoimmune diabetes mellitus patients are considered as appropriate.