Objective To observe the clinical anti-HBV-replication effect of IFN-a lb combined with large dose of thymopeptide on patients with chronic hepatitis B. Methods 77 patients with chronic hepatitis B whose HBeAg and HBV-DNA were positive were enrolled in this research and divided into two groups randomly:treatment group and control group.23 patients in control group were treated in the same procedure except without using thymopeptide. Results In treatment group,the negative rates of HBeAg and HBV-DNA were 64.8% and 68.5% by the and of the remedy.In control group,the percentage of the above two parameters were 39.1%and 43.5%respectively.The comparison of the three parameters between the two groups showed a significant difference(P0.05).No obvious toxic side reactions occurred in the course of treatment. Conclusion The antiviral effect could be enhanced by IFN-a lb combined with thymopeptide.