Abstract: OBJECTIVE To investigate the effect of Sophora flavescens combined with lamivudine on the expression of CYP1 A1 and CYP2 E1 in liver tissues of rats with hepatitis B infection. METHODS Forty SD rats were randomly divided into 8 in the control group, 8 in the model group, 12 in the lamivudine group, and 12 in the Sophora flavescens combined with lamivudine group. Hepatitis B viruses were injected into the abdominal cavity of the model group, the lamivudine group and the lamivudine group for 4 weeks to establish the rat model with hepatitis B infection. After the model was successfully established, flavonoids 10 mg/kg and lamivudine 10 mg/kg gavage were given to the rats once a day for 3 consecutive days. The control group was administered the same volume of saline intravenous or intragastrically, and the model group was intragastrically administered the same volume of saline. Blood was collected after modeling and intragastric administration, and liver function indicators, such as aspartate aminotransferase, alanine aminotransferase, total bilirubin were detected using a fully automatic biochemical analyzer. CytochromeP4501 A1 mRNA and CytochromeP4502 E1 mRNA expression levels were detected by Real-time quantitative PCR; CYP1 A1 and CYP2 E1 protein expression levels were detected by Western blot. RESULTS Compared with the model group, the HBV response rate and HBV-YMDD mutation rate in the lamivudine group significantly reduced（P＜0.01）, and the HBV-DNA conversion rate and the HBeAg conversion rate increased significantly（P＜0.05）. Levels of liver function indicators（AST, ALT, TBIL） were down-regulated significantly（P＜0.05）, and the mRNA and protein expression levels of CYP1 A1 and CYP2 E1 were significantly reduced（P＜0.01）. The HBV response rate and the HBV-YMDD mutation rate were significantly reduced after the combined treatment of Sophora flavescens and lamivudine, the HBV-DNA and HBeAg conversion rates were significantly increased, and the liver function indexes decreased significantly（P＜0.05）. The levels of expression mRNA and protein of CYP1 A1 and CYP2 E1 decreased significantly（P＜0.05）. CONCLUSION Sophora flavescens combined with lamivudine can reduce liver damage caused by hepatitis B infection, and its mechanism may be related to the inhibition of CYP1 A1 and CYP2 E1 expression.