Abstract: OBJECTIVE To investigate the therapeutical effect of dihydroartemisinin on bile duct ligation-induced liver fibrosis in rats. METHODS Hepatic fibrosis model was established by bile duct ligation， treatment groups in which rats received intraperitoneal injection of DHA at 14 mg/kg and colchicine treatment. At the end of the experiment， the rats were sacrificed， Blood was collected to exam Levels of alanine aminotransferase (ALT)， aspartate aminotransferase (AST)， and Bilirubin in serum samples. Hematoxylin and eosin (HE)， Masson’ s trichrome stain and sirius red collagen staining were used to Pathological changes in liver tissue. Western blotting analyses were used to evaluate the indicators related with HSC activation such as α-SMA， α 1(Ⅰ) collagen in liver tissue. Immunofluorescence was used to evaluate the expression of TGFβ-RⅡ in liver tissue. HSC-T6 was cultured in vitro and treated with DHA. Western blotting analyses were used to evaluate the expressions of α-SMA， α 1(Ⅰ) collagen， TGFβ-RⅡ， p-Smad2， and Smad2. RESULTS As shown in Serological indicators， compared with the control group， contents of serum ALT， AST， Bilirubin was significantly increased in the model group， DHA could decrease the serum levels of ALT， AST， Bilirubin. As shown in HE， Masson， and Sirius red staining， comparedwith the model group， DHA significantly alleviated liver pathology tissue and deposition of collagen fibers， and inhibited expression of α-SMA， α 1(Ⅰ) collagen and TGFβ-RⅡ， p-Smad2. CONCLUSION DHA had the protective effect on liver fibrosis induced by BDL， which was primarily related to inhibition of HSC activation and regulation of TGF -βII/Smad2 signaling pathways.