Abstract: Objective To establish the highly sensitive assay of hepatitis C virus core antigen（HCVcAg） and to assess its methodology.Methods HCVcAg-and DNA chain-labeled nanoparticle probe（NP） and HCVcAg-labeled magnetic microparticle probe（MMP） with monoclonal antibodies were prepared to form a MMP-HCVcAg-NP sandwich complex.DNA chain was then released by dehybridization.Hepatitis C virus was identified based on the presence of the released DNA chain detected by fluorescent quantitative PCR.Results The fluorescent quantitative bio-bar codes assay（FQ-BCA） of HCVcAg was established with a sensitivity of about 100fg/ml which was 10 times higher than that of conventional ELISA assay.Conclusion This study lays a foundation for establishing the highly sensitive HCV FQ-BCA assay of HCVcAg.