Background and Aims Among many bariatric-metabolic procedures, the single-anastomosis duodenal-ileal bypass with sleeve gastrectomy (SADI-S) is one of the most effective treatments for obese type 2 diabetes. However, there are few reports on SADI-S in China. Therefore, this study was conducted to investigate the efficacy of SADI-S in obese type 2 diabetes patients in China to provide a reference for future treatment choices.Methods The clinical data of 50 patients with obese type 2 diabetes undergoing SADI-S at China-Japan Union Hospital of Jilin University between October 2018 and August 2021 were retrospectively analyzed. Patients were analyzed for intraoperative and postoperative conditions (operative time, postoperative hospital stay and surgical complications), weight, body mass index (BMI), extra weight loss (%EWL), total weight loss (%TWL), fasting glucose, glycosylated hemoglobin, and complete remission rate of diabetes after surgery. Follow-up was completed as of August 2022.Results Of the 50 patients, 24 cases were males and 26 cases were females, with a mean age of 34 (28-43) years. All patients completed SADI-S surgery by laparoscopic (11 cases) or robotic (39 cases) approach without conversion to laparotomy, and no death occurred. The operative time was (187.9±37.9) min and the length of postoperative hospital stay was 6 (6-7) d. Surgical complications occurred in 3 patients (6%), which included two Clavien-Dindo Grade Ⅱ complications (abdominal fluid collections and anastomotic leakage) and one Clavien-Dindo grade Ⅲ complication (gastric leakage). The patient with anastomotic leakage was discharged after a combination of conservative treatments, including water fasting, total intravenous nutrition, and intravenous antibiotic therapy. The patient with gastric leakage was discharged after treatment with gastric fistula repair. The patients' weight, BMI, fasting glucose and glycosylated hemoglobin decreased significantly at 3, 6, 12 and 24 months after surgery compared with their preoperative values (all P<0.05). The %EWL values were (57.8±17.5)%, (78.3±18.6)%, (97.3±22.1)%, and (92.5±9.9)%, the %TWL values were 23.2 (19.9-25.9)%, 31.9 (29.3-33.7)%, 39.3 (34.7-45.2)%, 43.0 (39.1-47.1)% and the complete remission rates of type 2 diabetes were 82.0% (41/50), 95.7% (45/47), 100% (36/36), and 100% (8/8) respectively at 3, 6, 12, and 24 months after surgery. SADI-S yielded better efficacy against diabetes in patients with high ABCD scores than those with low ABCD scores at 3 and 6 months after surgery, and yielded remarkable efficacy against diabetes in patients with ABCD scores of all levels.Conclusion SADI-S has an excellent effect in treating obese type 2 diabetes in the Chinese population, but its long-term impact needs to be further observed.