Objective: To investigate the influence of interleukin 13 (IL-13) on activity of transforming growth factor-β1 (TGF-β1)/Smads signaling pathway in bile duct fibroblasts and the interventional effect of dexamethasone (Dex). Methods: Rabbit bile duct fibroblasts were isolated and cultured and then identified. Then, the bile duct fibroblasts were exposed to IL-13 or IL-13 plus different concentrations (0.01, 0.05 and 0.25 mg/mL) of Dex respectively for 48 h, using untreated bile duct fibroblasts as blank control. Afterwards, cell proliferation was assessed by CCK-8, the mRNA expressions of TGF-β1, Smad3 and Smad4 were determined by real-time PCR and the protein expressions of TGF-β1 and Smad4 were examined by Western blot. Results: In bile duct fibroblasts after exposure to IL-13 for 48 h, the cell proliferation was significantly increased, the mRNA expressions of TGF-β1, Smad3 and Smad4 and the protein expressions of TGF-β1 and Smad4 were significantly up-regulated (all P<0.05), and the above changes exerted by IL-13 were significantly inhibited by Dex addition in a certain concentration-dependent manner (part P<0.05). Conclusion: IL-13 can enhance the activity of TGF-β1/Smads pathway in bile duct fibroblasts, and weakening the activation of this signaling pathway may be one of the mechanisms of the inhibitory effect of Dex on benign biliary stricture.