Objective:To develop a system to screen for the effective siRNA sequence targeting HBs gene and to identify the interference efficiency.Methods:Three HBs-targeting siRNA segments (HBs-siRNA1,HBs-siRNA2,and HBs-siRNA3) were designed,synthesized and cloned into pSUPER vector to construct three recombinant plasmids pSUPER-HBs-siRNA,which were then transfected into human embryonic kidney 293T cells together with HBV plasmid.The transfection efficiency was observed 72 h later,the interference efficacies of the 3 segments were identified by real-time PCR and ELISA analysis,and the best one was identified.Results:Three recombinant plasmids of pSUPER-HBs-siRNA were constructed successfully and effectively transfected into 293T cells to induce RNAi,with a transfection rate higher than 70%.The results of real-time PCR and ELISA analysis showed that HBs-siRNA2 silenced the HBs gene expression by more than 80%.Compared with HBs-siRNA2,HBs-siRNA1 and HBs-siRNA3 did not demonstrate obvious interfering effect (P<0.05).Conclusion:We have successfully constructed 3 siRNA sequences targeting HBs,and pSUPER-HBs-siRNA2 can effectively silence HBs genes,which paves a way for future study.