Objective To establish the model of alcohol-induced hepatocyte steatosis in L-02 liver cells in vitro,investigate the relationship between cell damage,UCP2 gene expression and ethanol concentrations in L-02 cells of steatosis,and explore the protective effect of Hovenia Dulcis Thunb extracted liquid.Method Hovenia Dulcis Thunb extracted liquid at the most compatible dosage was applied to the L-02 cells of steatosis.Then UCP2 mRNA was detected by the semi-quantitative RT-PCR method.Results In steatosis model groups,UCP2 mRNA expression was downregulated ( P ＜0.05).In the steatosis groups treated with Hovenia Dulcis Thunb extracted liquid,UCP2 mRNA level was significantly increased compared to steatosis group ( its expression level increased from 0.4859 to 0.7442 after treatment of 0.6％ ethanol,P＜ 0.05).Conclusions Ethanol can down-regulate the UCP2 mRNA expression of L-02 cells in a certain period.The low expression of UCP2 mRNA is probably relevant to the occurrence of alcoholic fatty liver disease.Hovenia Dulcis Thunb can prevent from the cell toxicity of ethanol and decrease the degree of steatosis.Hovenia Dulcis Thunb extracted liquid can increase the expression level of UCP2 mRNA in the L-02 cells.