[Objective] The purpose was to explore the effect of porcine cathepsin S (cathepsin S, CTSS) on SVV (Seneca Valley virus, SVV) replication.[Methods] IBRS-2 cells were infected with SVV, and the regulation of endogenous CTSS expression by SVV infection was investigated by RT-qPCR at transcriptional levels. The effect of SVV infection on CTSS enzyme activity was determined by ELISA. The regulatory effects of overexpressed CTSS on SVV replication and antiviral cytokines induced by SVV were detected by Western blotting (WB) and RT-qPCR. The specific siRNA for CTSS was synthesized and the interference effect of siRNA on CTSS and the effect of CTSS interference on SVV replication were detected by WB and RT-qPCR.[Results] The expression of endogenous CTSS and the activity of CTSS enzyme were markedly up-regulated in IBRS-2 cells infected with SVV. SVV replication in IBRS-2 cells was significantly inhibited and the expression of host antiviral cytokines host antiviral cytokines was up-regulated by CTSS overexpression. siRNA-2947 down-regulate the expression of endogenous CTSS to promote SVV replication.[Conclusion]] CTSS inhibits SVV replication by enhancing the up-regulated expression of host antiviral cytokines. This study provided the reference basis for further exploring the role and mechanisms of host CTSS in anti-SVV innate immune response.