To evaluate the efficacy and nutrition of single-anastomosis duodenal-ileal bypass with sleeve gastrectomy (SADI-S) in Chinese obese patients in the first postoperative year. Clinical data of 66 obese patients who underwent SADI-S surgery at China-Japan Union Hospital of Jilin University from November 2018 to May 2022 were retrospectively collected. The weight, body mass index (BMI), percentage of excess weight loss (%EWL), and percentage of total weight loss (%TWL) were recorded at 3, 6, and 12 months after surgery. Moreover, metabolic disease remission and nutrient deficiencies were assessed at 1 year postoperatively. Overall, 66 patients (38 males and 28 females) were recruited, with a mean age of 35 (18–61) years and an average preoperative BMI of 42.94 kg/m2. Before surgery, 38 patients had type 2 diabetes mellitus (T2DM), 46 patients had hyperuricemia (HUA), 45 patients had hypertension (HTN), 35 patients had hyperlipidemia, 12 patients had hypercholesterolemia, 12 patients had hyper-low-density lipoproteinemia, and 14 patients had gastroesophageal reflux disease symptoms (GERD). All patients had undergone a DaVinci robotic or laparoscopic SADI-S surgery, and none converted to laparotomy or died. Four patients developed postoperative complications and were cured and discharged after conservative treatment or surgical treatment. At 3, 6 and 12 months, the average %EWL was 62.07 ± 26.56, 85.93 ± 27.92, and 106.65 ± 29.65%, %TWL was 22.67 ± 4.94, 32.10 ± 5.18, and 40.56 ± 7.89%, respectively. Fasting blood glucose (FBG), glycated hemoglobin (HbA1c), uric acid (UA), triglycerides (TG), blood pressure (BP), and other indexes were significantly lower after one year post-surgery compared with the preoperative period (P < 0.05). The remission rates of T2DM, HUA, HTN, hypertriglyceridemia, hypercholesterolemia, and hyper-low-density lipoproteinemia 1 year after surgery were 100, 65.2, 62.2, 94.3, 100, and100%, respectively. One year after surgery, the remission rate of GERD was 71.4% (10/14), the rate of new occurrence of GERD was 12.1% (8/66), and the overall incidence rate was 18.2% (12/66). Except for vitamin B12(vit B12), the other nutrient indexes were significantly decreased after 1 year of surgery relative to levels before surgery (P < 0.05). The deficiency rates for vitamin A (vit A), vitamin E (vit E), zinc ion (Zn), and folic acid (FA) were higher (45.5, 25.8, 24.2, and 16.7%, respectively); however, there were no related clinical symptoms. SADI-S had significant effects on weight loss and metabolic disease remission. The main nutrient deficiencies after SADI-S were vit A, vit E, Zn, and FA deficiencies. The long-term efficacy and safety of SADI-S warrant further follow-up.