Abstract: Objective Study the protective and therapeutic value of DNA vaccine in HCV infection.Methods The recombinant plasmid PEF-HCV was constructed by inserting the highly conserved HCV-core gene fragment into the eukaryotic expression vector PEF under the control of a EF-1Apromoter,and then was injected into the quadriceps muscles or inoculated subcutaneously into right and left flank of Balb/c mice.Results Within 3 weeks antibody to HCV core was detected in serums of mice injected recombinant pEF-HCV core,but the titers were low and the serum antibody level rised significantly in 7 days after the booster inject ion,no specific antibody was detected in other groups.Conclusion The results suggested that HCV core DNA-based immunization can induce HCV specific antibody,but the humoral immune response was weak at early stage.