ObjectiveTo analyze the species, distribution characteristics, and antimicrobial  susceptibility of pathogens from bile of patients with choledocholithiasis and biliary tract infection during and 48 hours after lithotomy under endoscopic retrograde cholangiopancreatography (ERCP), so as to provide guidance for clinical antimicrobial choice. MethodsPatients who performed lithotomy under ERCP for treating choledocholithiasis and biliary tract infection in a hospital between October 2015 and December 2016 were surveyed, bile from patients during lithotomy under ERCP (intraoperative group) and 48 hours after lithotomy by nasobiliary drainage (postoperative group) were performed bacterial culture and antimicrobial susceptibility testing. ResultsData of 117 patients were collected, positive bacterial culture rate of bile in intraoperative group and postoperative group were 73.50% and 47.86% respectively, there was significant difference between two groups (P<0.05). A total of 174 bacterial strains were isolated from 234 bile specimens in two groups, gramnegative bacteria, grampositive bacteria, and fungi were 138 (79.31%), 33 (18.97%), and 3 (1.72%) strains respectively; 105 strains were from intraoperative group and 69 were from postoperative group; there was no significant difference in the distribution of bacterial species between intraoperative group and postoperative group（P＞0.05）. The top 5 bacteria in intraoperative group and postoperative group were Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecalis, and Enterobacter cloacae. Susceptibility rates of Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa to 10 kinds of antimicrobial agents were all≥60.00%， resistance rates of Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa to piperacillin/tazobactam, ceftazidime, and levofloxacin were relatively higher; susceptibility rates of these three bacteria to imipenem and meropenem were all 100.00%. Among grampositive bacteria, susceptibility rates of Enterococcus faecium and Enterococcus faecalis to teicoplanin, vancomycin, and linezolid were all 100.00%. ConclusionGramnegative bacteria is the main pathogen causing biliary tract infection, patients with choledocholithiasis and biliary tract infection should perform lithotomy under ERCP as early as possible in case of no contraindication, so as to relieve biliary obstruction; combined antimicrobial use is suggested for the empiric antimicrobial treatment.