Compared with traditional treatment methods, surgery for diabetes not only frees patients from drug dependence, but also provides more stable sugar control than drug therapy alone. Therefore, in recent years, the number of patients choosing weight loss metabolic surgery to treat diabetes is gradually increasing. However, unlike traditional drug therapy, bariatric surgery has some limitations and is not suitable for all diabetic patients, only obese type 2 diabetic patients can obtain better treatment results through bariatric surgery. Moreover, the Chinese Guidelines for the Surgical Treatment of Obesity and Type 2 Diabetes (2019 Edition) also clearly states that non-obese type 1 diabetes cannot be treated by surgery. Director Wu Liangping, a weight loss and metabolic surgery expert from Youdao Doctor Group who participated in the development of the guideline, pointed out that the principle of weight loss and metabolic surgery to treat diabetes is to reduce insulin resistance by reducing body weight, restricting diet and absorption to directly reduce part of the blood glucose, so that the insulin secreted by itself can complete blood glucose regulation, and obese type 2 diabetes fits its treatment mechanism best, so it can obtain a good treatment effect. Non-obese type 1 diabetes patients are not recommended to be treated with surgery because the insulin resistance caused by obesity is not high and their own insulin secretion ability is completely lost, so it is difficult to get significant improvement even if they have surgery. Although bariatric metabolic surgery has been developed and improved over the decades, it still has limitations due to its therapeutic mechanism, so a detailed preoperative evaluation is needed before determining to do the surgery.