ObjectiveTo evaluate the effect of  Pegylated interferon (PEG IFN)α2a on treating chronic hepatitis C. MethodsSixtyeight chronic hepatitis C cases were divided into observation and control group, 36 cases in observation group received  PEG IFN α2a plus ribavirin, 32 cases in control group received interferon  plus ribavirin, HCV RNA and serum alanine transaminase (ALT) were detected in two groups before treatment, during treatment, at the end of 48week treatment and 24week of followup, the treatment effect was compared between two groups. ResultsAt the end of 48week treatment, virological  response rate and  biochemical response rate were both 88.89%in  observation group, and it was 75.00% and 81.25% respectively in control group, there were no significant difference in the treatment effect at the end of treatment between two groups( both P> 0.05). The early virological response rate and sustained virological response  rate was 47.22% and 80.55% respectively in observation  group, which was significantly higher than  12.50% and 31.25% respectively in control group (χ2=9.57, P＜0.05；χ2=16.84, P＜0.05; respectively); The relapse rate was 8.33% in  observation group, which was significantly lower than 43.75% in control group (χ2=11.33，P＜0.05).  ConclusionThe effect of  PEG IFN α2a on treating chronic hepatitis C is superior to IFN α2a .