The invention provides a host factor hPRDX5 with an anti-tumor effect, an encoding gene and application of the host factor, and belongs to the technical field of cancer treatment. The host factor hPRDX5 is a single protein component, has the advantages of good preparation repeatability and controllable quality, does not generate immunogenicity when applied to humans and has incomparable advantagescompared with ACBPs. The host gene hPRDX5 can significantly inhibit growth of in-situ pancreatic cancer tumors, and by studying the adjustment and control effects of the hPRDX5 on CD4, CD8, NKT and MDSCs cells in a tumor immunity micro-environment of a pancreatic cancer mouse, it is discovered that compared with a control group, the proportion of CD4+T, CD8+T and NKT cells in pancreatic tumor tissue is significantly increased after treatment by the hPRDX5. Therefore through application of the host factor hPRDX5 in preparation of anti-tumor drugs, the tumor load can be effectively reduced, andthe period of survival with tumors is prolonged.