Abstract: Objective B16-HPV16E7 tumor cells(E7-expression),B16-HPV16E7,were employed to explore the antitumor mechanisms of pcd-HPV16m E7-HSP70 DNA vaccine. Methods Flow cytometry was used to assess the effect of TNF-g on Fas expression on the surface of B16-HPV16E7 cells.IFN-γ and FasL levels from lymphocytes after pcd-HPV16m E7-HSP70 vaccination were measured by ELISA and flow cytometry.CTL assay was used to evaluate the role of Fas-FasL pathway on the anti-tumor ability of pcd-HPV16m E7-HSP70 vaccine. Results IFN-γ stimulation significantly increased Fas expression in B16-HPV16E7 cell line.pcd-HPV16mE7-HSP70 DNA vaccination significantly increased E7-specific lymphocytes and IFN-γ secretion in supernatants of cultured mouse spleen′s lymphocytes.In addition,the specific cytolytic activities of E7-specific lymphocytes against the tumor cells were partly inhibited by anti-FasL antibody pretreatment. Conclusion Pcd HPV16m E7-HSP70 DNA vaccine played an important anti-tumor role through Fas-FasL pathway.