Objective Rinse the common bile duct with 100 mL of 0.9% sodium chloride injection after choledocholithotomy to observe if it can improve the clearance rate of residual stones.Methods A study enrolled patients receiving endoscopic retrograde cholangiopancreatography (ERCP) and mechanical lithotripsy for calculus of common bile duct ( ≥ 12 mm) were conducted. After occlusion cholangiography confirmed common bile duct stone clearance, intraductal ultrasonography (IDUS) was performed to determine clearance scores based on the number of residual stones. The amounts of residual stones spotted via IDUS were graded, a large amount of stone fragments scored 1, a small amount of stone fragments scored 2, completely cleared common bile duct without any biliary sludge scored 3. After clearing calculus of common bile duct in ERCP and rinsing with 50 mL and 100 mL 0.9% sodium chloride injection, IDUS examination was performed and scored.Results No patient had common bile duct clearance scores of reached 3 without saline irrigation, 45 (40.18%) patients reached 3 with 50 mL 0.9% sodium chloride injection irrigation, and 99 (88.39%) patients reached 3 with 100 mL irrigation. Multivariate Logistic regression analysis showed that common bile duct diameter > 15 mm [odds ratio (OR＾) = 4.90, 95% confidence interval (CI): 1.19 ~ 22.57, P = 0.013], angulation of the distal common bile duct (the angle between the axis of the common bile duct and the ampulla axis of the common bile duct in cholangiography) ≤ 140°(OR＾ = 6.92, 95%CI: 1.83 ~ 38.98, P = 0.047) and duodenal diverticulum (OR＾ = 4.10, 95%CI: 1.14 ~ 16.90, P = 0.041) were independent risk factors for failure to rinse with 100 mL 0.9% sodium chloride injection.Conclusion Irrigation with 100 mL 0.9% sodium chloride injection can effectively remove the residual calculus of common bile duct after lithotripsy.