Objective To establish an animal model for biliary cast syndrome (BCS) of human and investigate the pathological mechanism for BCS. Methods Forty Japanese large-ear rabbits were divided into two groups at random. Biliary endepidermis was damaged with carbolic acid in experiment group rabbits, then a support tube was placed at the breakpoint of bile common duct in each experimental animal. Only support tube was placed at the breakpoint of bile common duct in control group. After four weeks, rabbits were executed, and the liver was dissected for pathological analysis. Results All experiment animals were operated successfully. Six rabbits died at 3rd week after operation. And all animals appeared as listlessness, poor appetite, changes in stool description and loss of weight. The symptoms of experimental group were obviously severe than in control group. There were adhesions at hepatic hilum and distensions at biliary tracts above intersect of common duct in experimental group, 4 rabbits appeared necrosis on biliary tract paries and bile retention hepatapostema in 6 experimental animals. Biliary cast was found in each experimental rabbit liver. There were mild adhesions at hepatic hilum, distensions at biliary tracts above intersect of common duct in control group. The biliary tract paries was slick, and no biliary cast was found in control animal liver. After the damage by carbolic acid, there were biliary endepidermis necrosis and defluvium defluxion in large bile duct at 24th h after operation. There were plenty of pink materials in liver exterior and interior biliary tract at 72nd h after operation. The biliary tract paries was infiltrated by white blood cells and part of biliary endepidermis was placed by flat epithelium. The biliary endepidermis was placed by fibrous tissue and fiat epithelium in large bile duct at 21st day after operation. Conclusion The animal model for BCS has been established successfully. BCS is contributed to the serious damage of biliary endepidermis. The formation of biliary cast and appearance of correlated symptoms are based on the sequentia inflammatory reaction. Key words: Biliary tract diseases; Biliary cast; Model, animal