Abstract：To observe the effects of simvastatin on hepatic fibrosis in rats and to study its possible mechanism, 60 male and female SD rats were randomly divided into control group, model group, and trial group. Rats of the model group were injected with tetrachloride (CCl4), rats of the trial group were injected with CCl4 and was gavaged with simvastatin 5mg·kg-1·d-1, and rats of the control group were injected with the equal volume of olive oil. Rats were all executed after 8 weeks, the contents of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured by full automatic biochemical analyzer. The pathological change of liver was observed under light microscope (hematoxylin-eosin staining). The expression of collagen I (Col I), collagen III (Col III), and Transfer Growth Factor-β1 (TGF-β1) were detected by immunohistochemistry. The results show that comparing the trial group with the model group, the inflammation and fibrosis are decreased in pathological sections, the expressions of Col I, Col III and TGF-β1 in the liver tissues are remarkably decreased (P<0.05), the contents of ALT and AST are decreased (P<0.05). Simvastatin can inhibit liver fibrosis induced by CCl4. The mechanism may be attributed to its effect of downregulating TGF-β1, Col I and Col III.