OBJECTIVE： To study the improvement effect of Poria cocos peels water extract （PWE） on liver fibrosis in rats induced by carbon tetrachloride （CCl4）. METHODS： 84 rats were randomly divided into blank control group， solvent control group， model control group， positive control group （Compound biejia ruangan tablet， 0.75 g/kg）， PWE low-dose， medium-dose， high-dose groups （0.9， 1.8， 3.6 g/kg， calculated by crude drugs）， 12 in each group. Except for blank control group and solvent control group （ip vegetable oil）， other groups received CCl4-vegetable oil solution to reduce liver fibrosis model， ip. After modeling， each administration group received related medicines， ig， other 3 groups received equal volume of normal saline， once a day， for 4 weeks. After administration， enzyme-linked immunosorbent assay was used to detect the aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， laminin （LN）， hyaluronic acid （HA）， hydroxyproline （Hyp） contents in serum and reduced glutathione （GSH）， superoxide dismutase （SOD）， malondialdehyde （MDA） contents in liver tissue of rats； HE staining and Masson staining were adopted to observe the pathological changes of liver tissue. RESULTS： Compared with blank control group， indexes of rats in solvent control group had no obvious changes （P＞0.05）. AST， ALT， LN， HA， Hyp contents in serum and MDA content in liver tissue in model control group were significantly increased （P＜0.05）； GSH， SOD contents in liver tissue were significantly reduced （P＜0.05）； and liver tissue showed obvious fibrosis lesions. Compared with model control group， AST， ALT， LN， HA， Hyp contents in serum and MDA content in liver tissue in PWE medium-dose， high-dose groups were significantly reduced （P＜0.05）； GSH， SOD contents in liver tissue were significantly increased （P＜0.05）； fibrosis degree of liver tissue was obviously relieved. CONCLUSIONS： PWE shows good improvement effect on liver fibrosis of rats induced by CCl4， which may be related to inhibiting the lipid peroxidation.