Abstract: Objective To study the IL-17 and IL-22 level in chronic HBV infection patients with entire response to pegylated interferon α-2a therapy and its clinical significance. Methods Serum was isolated from venous blood of HBV-infected patients with entire response to pegylated interferon α-2a therapy,those not receiving pegylated interferon α-2a therapy and health controls,respectively.Their serum ALT,HBV-DNA,HBV-M,IL-17,and IL-22 levels were measured. Results The serum IL-17 level was significantly lower in patients with entire response to pegylated interferon α-2a therapy than in those not receiving pegylated interferon α-2a therapy.The IL-22 level was higher in patients with entire response to pegylated interferon α-2a therapy than in those not receiving pegylated interferon α-2a therapy,but lower than in control group,which began to decrease gradually 6 months after treatment. Conclusion Treatment of chronic HBV infection with pegylated interferon α-2a can decrease inflammation and clear HBV in liver.