Abstract: Objective　To assess the effect of heat shock protein 70 of BCG (BCG HSP70) gene transfection on tumorigenicity and immunogenicity of murine lymphocytic leukemia cells (L1210). Methods BCG HSP70 gene was transfected onto the surface of murine lymphocytic leukemia cells (L1210) by lipofectamine 2000. And then the positive clone (L1210-HSP70) highly expressing HSP70 was selected as the tumor vaccine to study the tumorigenicity experiments in nude mice and syngeneic mice, the therapeutic experiments, and the immunoprotective effects. Results The expression of BCG HSP70 on the L1210 cells surface was detected, and the L1210-HSP70 cells had the same tumorigenicity as the parental L1210 cells did. Tumorigenicity experiments in syngeneic mice: In L1210-HSP70 group, tumor growth was slow or without the formation of tumor. As compared with L1210 group and L1210-neo group the mice survival time was significantly prolonged, showing a marked stimulating effect on L1210 specific Th1 cells,. Tumor-bearing mice showed complete coagulation necrosis and abundant CD8+ T lymphocyte infiltration (P<0.05). The tumor vaccine of L1210-HSP70 cells had the antitumor therapeutic efficacy and immune protection effect, demonstrating that the tumor growth was significantly inhibited, tumor diameter was markedly reduced and the survival time of tumor-bearing DBA/2 mice was further prolonged. Conclusions BCG HSP70 gene transfection could effectively improve the immunogenicity of tumor cells, activate specific T cells and enhance the anti-tumor immunity in vivo. Meanwhile, the host anti-tumor immunity could be enhanced.