Objective: To distinguish clinical features, safety and efficiency of endoscopic retrograde cholangiopancreatography (ERCP) in patients after bilioenteric anstomosis based on retrospectively analyzed clinical data and endoscopy procedures. Methods: Data extracted from patients after bilioenteric anstomosis due to biliary disease treated with ERCP from January 2005 to December 2021 in the Department of Gastroenterology, Peking University Third Hospital were retrospectively analyzed. Clinical data and endoscopic pictures were reevaluated and analyzed. The patients were divided into three groups, including the patients with choledochoduodenostomy (CDD), Roux-en-Y hepaticojejunostomy (RYHJ) and Whipple. Differences between ERCP success and failure were conducted. Results: In the study, 89 cases with 132 ERCP procedures were involved, 9-80 years old, median 57 years old, containing 4 CDD, 30 RYHJ, 54 Whipple and 1 bile duct ileocecal anastomosis patients; The time between ERCP and surgery were 30 (1-40), 2.75 (0.5-14), 2 (0.3-19), and 10 years, respectively; The time between surgery and symptom were 240 (3-360), 12 (1-156), 22 (0-216), and 60 months, respectively. Fifty percent of CDD could succeed only under local anaesthesia, RYHJ (96.7%) and Whipple (100.0%) needed under general anaesthesia (P < 0.001). Successful first entry rates of CDD, RYHJ and Whipple were 100.0%, 40.0% and 77.8%, respectively. After changing the endoscopy type, successful entry rate could increase to 43.3% of RYHJ and 83.3% of Whipple. The successful entry rate of different anastomotic methods was significant (P < 0.001). The cannulation success rates of CDD, RYHJ and Whipple were 100.0%, 53.8% and 86.7% respectively, with significant difference between the groups (P=0.031). ERCP success rates of CDD, RYHJ and Whipple were 100.0%, 33.3% and 78.8% respectively, with significant difference between the groups (P < 0.001). Complications were found in 23.9% (21/88) patients, including infection (14.8%), pancreatitis (9.2%), bleeding (3.4%), and perforation (2.3%) ranked by incidence. Causes of ERCP in post bilioenteric anstomosis were anastomotic stenosis (50.0%, benign 39.3%, malignant 10.7%), choledocholithiasis (37.5%) and reflux cholangitis (12.5%). Anastomotic method was the only predicting factor of ERCP success in patients after bilioenteric anstomosis (OR=7, 95%CI: 2.591-18.912, P < 0.001). Conclusion: ERCP in post bilioenteric anstomosis patients with gastrointestinal reconstruction need general anaesthe-sia, with good safety and efficiency. The successful rate of RYHJ was significantly lower than Whipple. Anastomotic method was the only predicting factor of ERCP success.