The level of intracellular keratin 8(KRT-8) is associated with liver diseases, whose expression is increased in hepatitis C virus(HCV)-infected patients with hepatocarcinoma and in cultural cells infected with HCV. However, it is not clear whether KRT-8 will impact HCV replication. In this paper, the HCV replication was analyzed in response to high expression and silence of KRT-8. The inhibitory activities against wild-type and mutant HCV were also analyzed by silence of KRT-8 or combined with known anti-HCV drug telaprevir. Results showed that the protein level of KRT-8 was increased in proportion with the HCV replication. The high expression was found to facilitate HCV replication, while the silence of KRT-8 was able to inhibit HCV replication and enhanced the anti-HCV activity of telaprevir. It also inhibited A156 T and D168 V mutant HCV, which are resistant to protease inhibitors. These results suggest that KRT-8 is a co-factor for HCV replication. Down-regulation of KRT-8 can inhibit wild type and mutant HCV replication to enhance the anti-HCV activity of known anti-HCV drugs. Therefore, KRT-8 may be a new target in the development of anti-HCV agents.