All patients with a clear diagnosis of T2DM and a body mass index (BMI) ≥ 27,5 kg/m2, who in principle have poor results or cannot tolerate after standard non-surgical treatment, can be considered for surgical treatment as long as there are no obvious contraindications to surgery. Better treatment results can be expected when patients meet the following conditions: (1) in principle, age 18-65 years; (2) duration of T2DM ≤ 15 years; (3) islet reserve function above 1/2 of the lower limit of normal and C-peptide ≥ 1/2 of the lower limit of normal. At the same time, patients are willing to assume the risk of potential complications of surgery, understand the importance of postoperative lifestyle changes and are willing to tolerate them, and can The patients’ willingness to bear the risk of potential complications, understand the importance of postoperative lifestyle changes and be willing to tolerate them, and actively cooperate with postoperative follow-up were also factors to be considered for surgery selection. Since most Chinese are abdominally obese and at higher risk of cardiovascular and other complications, surgery should be more actively considered when the waist circumference is ≥90 cm in men and ≥80 cm in women. For patients with BMI <27, 5 kg/m2, it is not appropriate to perform a wide range of promotion for the time being. However, if medical treatment is not effective or not tolerated by the patient, and if the patient strongly requests it, surgical treatment can be tried according to the pathway of clinical trials after permission from the ethics committee. For patients with BMI <24 kg/m2, surgical treatment will not be considered.