Objective-- To explore the effects of siRNA targeting to Virion host shutoff protein (VHS) on HSV-1 replication in vero cell. Methods--Three kinds of siRNAs were Tran scripted in vitro using T7RNA polymerase according to the principle of siRNA design. The Vero cells were transfected with siRNA using lipofectamine 2000 followed by HSV-1 infection. The activity of vero cells were detected by MTT method and virus titer were monitored from 12h to 72h after infection with single step growth curve assay. Results--VHS-specific siRNAs were apparently able to decrease the dead numbers of vero cells infected by HSV-1, and the virus titer showed the apparent difference between two groups (PP