Laparoscopic Roux-en-Y gastric bypass (LRYGB) is a classic bariatric and metabolic surgery, which is a combination of limiting intake and reducing absorption. LRYGB has a higher remission rate for type 2 diabetes, which may be related to the change of gastrointestinal hormone secretion and the effect of bypassing duodenum on the function of islet cells. LRYGB could be used as the first choice for obese patients or super obese patients with severe reflux esophagitis or metabolic syndrome. The main points of this operation include: ① A gastric pouch should be established under the cardia with isolated gastric fundus, ensuring a volume of < 30 ml; ② The total length of jejunum including biliopancreatic branch and food branch should be more than 200 cm; ③ Diameter of the GJ anastomosis should be < 1.5 cm; ④ Mesentery defect should be closed to prevent internal hernia.