OBJECTIVE：To study the pr otective effect of schisandrin A （SA）on CCl 4-induced liver fibrosis model mice and its mechanism. METHODS ：Mice were randomly divided into blank control group ，model group ，silymarin group （positive control，100 mg/kg），SA low-dose and high-dose groups （20，40 mg/kg），with 10 mice in each group. Except for blank control group，other groups were given CCl 4 subcutaneously to induce liver fibrosis model. After successful modeling ，administration groups were given relevant medicine intragastrically ，once a day ，for consecutive 6 weeks；blank control group and model group were given constant volume of 0.5％sodium carboxymethyl cellulose solution intragastrically by the same way. HE staining was used to observe the pathological changes of liver tissue in mice. UV spectrophotometry and ELISA assay were adopted to detect the serum levels of liver injury indexes （ALT and AST ）and the contents of inflammatory factors （TNF-α，IL-1β，IL-6）. Western blotting assay was used to detect the expression of NOD like receptor protein 3（NLRP3）/NF-κB and TGF-β/Smad signaling pathway protein. RESULTS ：Compared with blank control group ，obvious pathological changes of liver fibrosis were observed in model group. The serum levels of liver injury indexes and contents of inflammatory factors were significantly increased （P＜0.01）. The expression of NLRP 3，apoptosis associated spot-like protein ，Caspase-1 and IL- 1β，TGF-β1 and ratios ofp-NF-κB p65/NF-κB p65，p-IκBα/IκBα，p-Samd3/Smad3 were increased significantly （P＜0.01）. Compared with model group ，SA could significantly relieve hepatic fibrosis in mice ，reduce serum levels of liver injury indexes and contents of inflammatory factors ，as well as the expression of NLRP 3/NF-κB and TGF-β/Smad signaling pathway protein and phosphorylation level（P＜0.01）. CONCLUSIONS ： SA can effectively relieve liver injury and inflammation of CCl 4-induced hepatic fibrosis model mice ，which may be through the regulation of NLRP 3/NF-κB and TGF-β/Smad3 signaling pathways ，thus inhibiting the process of liver fibrosis.