Objective:To explore a fast method to identify and confirm suspected clonorchis sinensis infection.Methods:For suspected clonorchis sinensis infection, the clonorchiasis serum antibody was detected first with ELISA. If the antibody was positive, the fecal examination for eggs was performed. If the fecal examination was negative, duodenal drainage under gastroscopy was recommended to detect eggs from the drainage fluid.Results:A total of 126 patients met the requirements and aged 54.14±13.33 (24- 87). There were 83 cases (65.87%, 83/126) with eggs positive in the drainage fluid, of which 53 cases were male, aged 55.91±11.47 (30-86), and 30 cases female, aged 55.87± 13.85(30-87). There was no significant difference in age between males and females( P>0.05). The time of catheterization (T1) of 126 cases was 3.79 ±1.45 min. The time of drainage (T2) of 126 cases was 31.39 ±14.29 min. There was no significant difference in T1 or T2 between the positive group and the negative group( P>0.05). The detection rates of eggs were 91.57% (76 cases) in intrahepatic bile duct drainage, 81.93% (68 cases) in the bile-cyst juice and 75.90% (63 cases) in the common bile duct fluid. No serious adverse reactions occurred during or after the operation. Conclusion:The detection rate of clonorchiosis sinensis can be effectively improved by the combination of clonorchiasis serum antibody test and gastroscopy-guided duodenal drainage.