Abstract: Objective To study the clinical efficacy of PegIFN α-2a in the therapy of CHB.Methods One hundred and eighty cases of CHB were randomly divided into PegIFN α-2a and IFN-α groups to observe ALT, HBV DNA, viral markers and serum hepatic fibrosis indexes including PCⅢ, CⅣ, LN, HA.Results At the end of the treatment and after 6 months, the decrease of HBV DNA level, the negative rate of HBV DNA and HBeAg, the positive rate of HBeAb were higher in PegIFN α-2a group than those in IFN-α group (P<0.05) , and the serum levels of PCⅢ, CⅣ, LN, HA were much lower in PegIFNα-2a than those in IFN-α groups (P<0.01) .Conclusions Peg IFNα-2a is effective in the therapy of CHB.The major adverse events included fever, leukopenia and thrombocytopenia, and there was no serious adverse events.