Objective: To investigate the effects of conditionally replicative adenovirus, which expresses short interference RNA-targeting Ki67 gene (Ki67-siRNA) with G250 promoter, on the growth of human renal cell carcinoma in nude mice.Methods: Human clear cell renal cell carcinoma (786-0) cells were transplanted into BALB/c nude mice.After the model was successfully developed, 40 mice were randomly divided into four groups, namely, Ad-Ki67, G250-EGFP, G250-Ki67,and PBS (control) groups.Different viruses were directly injected into the tumor on alternate days for three times[7×108 PFU (0.2 mL) each time]; 0.2 mL of PBS was used for the control group.Four nude mice in each group were randomly sacrificed seven days after the injection of the virus and tumor dislodgment.Immunohistochemistry staining was performed to detect the protein expression of Ki67 and E1A.