Objective To investigate the relationship between the expression of the Smad4,TGF-?_1 and T?R II and the possible mechanisms in the development of cholangiocarcinoma. Methods Immunohistochemical SABC method was used to examine the expression of Smad4,TGF-?_1 and T?R II in 49 cases of cholangiocarcinoma and 8 nomal common bile duct.Results The expression rates of Smad4,TGF-?_1 and T?R II in cholangiocarcinoma were (40.82)%(20/49),71.43%(35/49) and 36.73%(18/49) respectively; in normal common bile duct tissues were 87.50(7/8),12.50%(1/8) and 100%(8/8) respectively. There was a significant relationship between the (expression) of TGF-?_1 and clinical stage, and tumor metastasis (P