Objective To clone and express hypervariable region 1 (HVR1) fragments of different genotypes of HCV strains from different cities of China.Then detect the reactivity of the expressed HVR1 fusion proteins with sera of chronic he-patitis C patients to analyzing it's signification in clinical utilization. Methods HVR1 genes of four HCV strains (genotype 1b and 2a) were amplified from pGEMT-E2 plasmids and cloned into pQE40 vectors, respectively to construct four recombinant prokaryotic expression plasmids which expressed HVR1 as fusion proteins with DHFR in Escherichia coli strain TG1. Then we used the purified DHFR-HVR1 proteins to detect the anti-HVR1 antibodies in 70 serum samples of chronic hepatitis C patients. Results Four DHFR- HVR1 fusion proteins were successfully expressed in E.coli (320～ 800 ?g fusion proteins per 100 ml culture). Each fusion protein (SH1b, BJ1b, SD1b and SD2a) reacted with 72.8%(51/70), 60%(42/70), 48.6%(34/70), and 58.6%(41/30) of the anti-HCV positive patients' sera, respectively by ELISA. 57% (4/7) of the non responders' sera taken before therapy reacted with all four HVR1 fusion proteins, while only 15.3% (2/13) of the sera from responders reacted with all of them. The A values of sera from IFN therapy responders were significantly higher than non responders (P