Ms. Song is 58 years old and has been suffering from type 2 diabetes for 12 years. Now she has to take several oral hypoglycemic drugs in addition to 50U of insulin every day, but even so, her blood sugar is still not well controlled and her glycosylated hemoglobin (HbA1c) is around 8%. Her weight was also distressing, as she was only 160cm tall and weighed over 90kg. During her outpatient visit, the doctor took a detailed medical history and did a thorough examination and thought that surgical treatment for diabetes could be considered. Ms. Song was surprised that diabetes had always been treated medically, how could open surgery also treat diabetes? In fact, the surgical treatment of diabetes was a very accidental discovery. In the 1980s, bariatric surgery was used to treat obese patients, and long-term follow-up revealed that obese patients lost significant weight after bariatric surgery, and the accompanying type 2 diabetes also improved to varying degrees, and many patients did not even need to take glucose-lowering drugs or insulin injections. Through these decades of clinical practice, especially in the last two decades, we have basically mastered the modalities and mechanisms of surgical treatment of diabetes mellitus. However, the cure rate of diabetes differs greatly among different surgical procedures. Foreign data show that: biliopancreatic bypass has the best effect and the remission rate of diabetes reaches 98.8%, but it is less used clinically because the procedure is more complicated and has more postoperative complications; the cure rate of gastric diversion can reach 83.7% and has fewer complications, so it is a more used procedure in the clinic at present; the procedure of gastric bundle is simple, but the remission rate is only 47.9%. Gastric banding is a simple procedure, but the remission rate is only 47.9%, so it is rarely used in clinical practice. At present, gastric diversion is mainly for patients with severe overweight type 2 diabetes mellitus, and the following conditions should be met: (1) age not older than 65 years; (2) duration of diabetes mellitus not older than 15 years; (3) islet reserve function in fair, C-peptide ≥ 1/2 of the low limit of normal. (4) no alcoholism and long-term drug dependence, mental and intellectual impairment; understand the procedure of weight loss surgery, and understand and accept the risk of potential complications of surgery; willing to (5) They are willing to accept postoperative lifestyle and dietary changes, and can cooperate with long-term postoperative follow-up. We do not recommend surgery for those patients with type 2 diabetes who are moderately or slightly obese. It should be reminded that long-term vitamins, trace elements and calcium tablets are needed to prevent anemia, osteoporosis and malnutrition after surgery. (2) Rapid weight loss and improvement of insulin resistance, and most patients’ body shape can return to a moderate state about six months after surgery; (3) Blood glucose quickly reaches the standard, and because the surgery changes the anatomical order of the gastrointestinal tract, its gastrointestinal The secretion pattern of hormones is also changed accordingly, which is the main mechanism of surgical hypoglycemia. Most patients can reach the blood glucose standard within a short period of time without medication or with a very small dose of hypoglycemic medication. Ms. Song followed the doctor’s advice and the surgery was completed successfully. Her weight has decreased by 18 kg in 3 months, all her original diabetic medications have been stopped, and her blood sugar is very well controlled, with fasting blood sugar at 6-7 mmol/L and postprandial blood sugar not exceeding 9 mmol/L. Her original proteinuria has disappeared, and she has more confidence in overcoming the disease!