Abstract： Objective To investigate the diagnostic value and feasibility of PTC diagnosis on pancreaticobiliary maljunction (IBM), and to summarize the PTC radiological characteristics of PBM. Methods Clinical findings and cholangiopancreatographic results were analyzed retrospectively for a group of consecutive 363 patients with obstructive jaundice receiving the PTCD therapy. Meanwhile the standard selected for cases and diagnostic conditions were established. The length and diameter of pancreaticobiliary common duct, the diameter of pancreatic duct and common bile duct and the confluence angle were measured respectively. The t test and rank sum test were used to analyze the result statistically. Results Thirty-eight cases were radiologicaUy diagnosed as PBM owing to the reference standard and the detection rate was 10.5% (38/363). The length of common duct was (12.6±7.9)mm. The significant difference existed between it and normal value (6ram) (t=5.15 , P <0.05). The site of duodenal papilla had influence on the length of common duct. The diameter of common bile duct, pancreatic duct and common duct near the confluence are (3.7±1.9 ) mm, (2.4±1.3) mm, (3.3±1.4 ) mm, respectively. There was no statistical difference between them and the normal value (t=1.79,2.85,5.72, P>0.05). Fifteen patients' duodenal papilla located the middle of descending duodenum. The length of common duct was (10.6±9.1)mm , the confluence angle was 51.1°±28.0°, the number of the duodenal papilla locating in the inferior 1/3 of descending duodenum, juncture , horizontal part of duodenum was 10, 8,5, respectively. The length of common duet were (9.9±3.7), ( 18.6±8.9), ( 13.9±3.5 ) mm, respectively. The confluence angle were 54.0°±18.6°、48.7°±12.6°、74.4°±18.5°, respectively . The site of duodenal papilla had significant influence on the length of common duct(X2=14.51, P <0.05). Conclusion PTC is a safe, feasible, method to diagnose PBM, and it demonstrates the characteristic findings of PBM.