Objective To compare the antiviral effects of lamivudine and entecavir for patients with chronic hepatitis B. Methods 60 CHB patients were divided into two groupslamivudine group(30 cases)and entecavir group(30 cases). Liver and kidney function,HBV DNA and HBV serum markers were examined regularly. And ALT normalization,un-detectable HBV DNA and their adverse reactions were observed at 12,24 and 48 weeks. Results There was no signifi-cant difference in ALT normalization,undetectable HBV DNA between lamivudine group and entecavir group although there were higher rates of entecavir group after treatment. However, there was a significant difference in reproduction number of HBV DNA between two groups after 24 weeks,and there were less reproduction numbers of HBV DNA of entecavir group. Two groups of patients had sustained response data. Adverse reactions did not occur during treatment. Conclusion Entecavir is more effective in inhibiting reproduction of HBV than that of lamivudine.