Objective：To confirm effects of bifidobacterium infantis mediated herpes simplex virus thymidine kinase（HSV-TK）/ganci－clovir（GCV） suicide gene system on the treatment of renal cell carcinoma in nude mice and to detect the induction of apoptosis and activaton of nuclear factor-κB（NF-κB） signaling pathway in renal cell carcinoma. Methods：Tumor cells which obtained through di－gestion of subcutaneous tumor were cultured and then subcutaneously injected into the right flank of the test mice.Animals were ran－domly divided into four groups：BI-pGEX-TK/GCV treatment group（recombinant plasmid group），BI-pGEX-5X-1/GCV group （empty plasmid group），BI/GCV group（empty BI group） and normal saline/GCV control group（normal saline group）. Either saline or drug was injected through tail vein，followed by intraperitoneal injection of GCV. The quality of life was recorded after 4 weeks of treatment and tumor weight was also evaluated.Apoptosis of tumor was detected by TUNEL assay. Expression of Rel A and Caspase-3 was assessed through qRT-PCR and Western blot. Results：（1）Quality of life of recombinant group was better and tumor weight of recombinant group was significantly lower compared with those of empty plasmid group，empty BI group and normal saline group（P=0.006，P=0.003）. （2）Different degrees of apoptosis of tumor cells in each group were detected by TUNEL assay，most obvions in recombinant plasmid group（P=0.000）. （3）More importantly，qRT-PCR and Western blot further demonstrated that the recombinant plasmid group had higher level of Caspase-3 protein expression than empty plasmid group，empty BI group and normal saline group（P=0.000），in contrast，the level of Rel A protein expression was the lowest（P=0.000）. Conclusion：Bifidobacterium infantis-mediated HSV-TK/GCV suicide gene therapy system induce apoptosis of tumor cells in renal cell carcinoma possibly by affecting the NF-κB signaling pathway，which play a tumor promoter role.