To compare the clinical efficacy of gastric bypass in obese patients with T2DM with different BMI. Serum leptin, adiponectin, triglyceride (TG), cholesterol (CHOL) were measured as the indicators to show clinical efficacy after laparoscopic gastric bypass surgery (LRYGB). For patients with high BMI and patients with low BMI, the therapeutic effect of LRYGB surgical diabetes is more significant. The postoperative remission rate of diabetes in the high BMI group was not correlated with the preoperative lipid metabolism index but was positively correlated with the postoperative lipid metabolism index CHOL, TG, leptin, adiponectin. The postoperative remission rate of diabetes in the low BMI group was positively correlated with the preoperative abnormal lipid metabolism of the patients, and positively correlated with the postoperative remission of leptin and adiponectin, but was not correlated with the postoperative remission of total CHOL and TG. The increase of serum adiponectin level and the decrease of leptin resistance after LRYGB surgery restored the metabolic balance of leptin and adiponectin, improved insulin resistance (IR), and thus improved blood glucose level. Therefore, LRYGB has a definite therapeutic effect on obese patients with T2DM, and elevated adiponectin and improved leptin resistance are some of the mechanisms of surgical treatment of diabetes.