In this cohort study, patients with chronic hepatitis B who prior participated in TB1211IFN study and received at least 39 doses of peginterferon alfa will be enrolled. HBsAg/anti-HBs level, HBeAg/anti-HBe level, Serum HBV DNA load and alanine transaminase level will be test every year from the second year to the fifth year after the ending of peginterferon alfa treatment, and long-term benefit of interferon treatment will be evaluated.