Abstract: Objective To induce renal transplantation tolerance by CTLA4-Ig adenovirus gene therapy in allogeneic rats and study the relative mechanisms of transplantation tolerance.Methods The kidney of SD rats were transfected with CTLA4-Ig gene-recombined adenovirus.After the orthotopic renal transplantation between SD and Wistar rats was conducted,all the rats were divided into 3 groups:group I was the control;rats in group II were perfused with empty EGFP and there in group Ⅲ with CTLA4-Ig adenovirus. The allograft survival time and the allograft funtion between the three groups were compared. Result The survival time was significantly longer in rat of group Ⅲ than in other 2 groups(31.3 ±6.8 days vs 8.2 士 1.2 days and 8.0 士 1.6 days). The serum creatinine of transfection group at 7th and 14th postoperative days was lower than that of controls at 7th postoperative day. Conclusion Local transfection of CTLA4-Ig gene can augment the tolerance and prolong the survival time of renal allograft significantly.