〔Abstract〕 Objective To study the mechanism of the treatment of metabolism associated steatohepatitis(MASH) in rats with Xiaoyao Wan. Methods Twenty-four SD male rats were randomly divided into control group(CON group,n=8) and model group(n=8). The model group was given high-fat diet, carbon tetrachloride(CCl4) subcutaneous injection, hunger and satiety disorder and tail clamping for four weeks to establish the MASH model, and the rats were randomly divided into the MOD group and the Xiaoyao Wan group(XYW group), with 8 rats in each group. The rats of the XYW group were given Xiaoyao Wan, the other two groups were given normal saline. Four weeks after administration, the serum biochemical indexes and oxidative stress indexes of rats in different groups were detected. The pathological sections of rat liver tissue were observed by hematoxylin-eosin(HE) staining and oil red O staining. The expression of cytochrome P450 2E1(CYP2E1), factor-related apoptosis ligand(FasL), tumor necrosis factor-α(TNF-α) and tumor growth factor-β1(TGF-β1) in rat liver were detected by Western blot method. The relative contents of CYP2E1, FasL, TNF-α and TGF-β1 mRNA in liver tissue were detected by RT-qPCR. Results The general condition of rats in the XYW group was significantly improved compared with the MOD group; the level of hepatic index was significant decrease compared with the MOD group(P<0.01) and the level of body mass index was significant increase compared with the MOD group(P<0.01); the serum levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol, aspartate aminotransferase, alanine aminotransferase, malondialdehyde, monocyte chemotactic protein-1, TNF-α, and interleukin(IL)-18 were significantly reduced compared with the MOD group(allP<0.05), and the levels of high-density lipoprotein cholesterol, superoxide dismutase, and IL-10 were significantly elevated compared with the MOD group(allP<0.05); the content of lipid droplets in hepatocytes of rats was significantly reduced compared with the MOD group under light microscope; the protein levels of CYP2E1, FasL, TNF-α and TGF-β1 in liver tissues were significantly reduced compared with the MOD group(allP<0.05), and the relative contents of CYP2E1, FasL, TNF-α and TGF-β1 mRNA were significantly reduced compared with the MOD group(allP<0.05). Conclusion Xiaoyao Wan can regulate the expression of CYP2E1, FasL, TNF-α and TGF-β1 in the liver tissue of MASH rats by reducing the accumulation of fat in the liver, so as to achieve the purpose of treating MASH.