Objective To explore the causes and management of postoperative complications of laparoscopic Roux-en-Y gastric bypass (LRYGB).Methods The retrospective cross-sectional study was conducted.The clinical data of 450 patients with metabolic diseases who underwent LRYGB between June 2004 and November 2016 were collected,including 283 (58 in hospital consultation) in the First Affiliated Hospital of Jinan University,140 in the Jihua Hospital Affiliated to Jinan University and 27 in the Zhengzhou Hospital of Jinan University.Observation indicators:situations of surgical completion,follow-up situations,occurrence,treatment and prognosis of complications.Follow-up using outpatient examination and telephone interview was performed to detect postoperative complications once at month 1,3,6 and 12 within 1 year postoperatively and once every year after 1 year postoperatively up to March 2017.Measurement data with skewed distribution were described as M (range).Count data were evaluated by the ratio,and comparison between groups was analyzed using the chi-square test.Results All the 450 patients with metabolic diseases underwent successful LRYGB,including 50 receiving LRYGB during surgical internship period and 400 receiving LRYGB after surgical internship period,without conversion to open surgery.All the 450 patients were followed up for 70 months (range,1-153 months).Twenty-seven patients had postoperative complications,with an incidence of 6.00％ (27/450).The incidence of postoperative complications was 20.00％(10/50) in 50 patients receiving LRYGB during surgical internship period and 4.25％ (17/400) in 400 patients receiving LRYGB after surgical internship period,with a statistically significant difference (x2 =16.86,P＜ 0.05).Of 27 patients with postoperative complications,1 was complicated with fulminant acute pancreatitis and died from multiple organ failure at day 15 postoperatively,5 with intra-abdominal bleeding,2 with anastomotic leakage,3 with gastrojejunal anastomosis stenosis,2 with gastrojejunal anastomosis ulcer,1 with improper anastomosis,1 with respiratory failure,1 with umbilicus infection,3 with internal hernia,2 with dumping syndrome,6 with weight-loss failure (1 refused to undergo revision surgery),and patients with postoperative complications were improved or cured by surgery or conservative treatment except one death.Conclusions The incidence of complications in patients receiving LRYGB after surgical internship period is significantly reduced,and complications needs to make the individualized treatment plan.