Abstract: objective To investigate the effect of interleukin-24 gene (IL-24) combined with As2O3 on renal cancer cell Ketr-3. Methods Ketr-3 cells were seeded onto 6-well plates and divided into 4 groups, PBS group (phosphate buffer saline), As2O3 group(As2O3=5μg?mL-1), IL-24 group(pCDNA3.1-IL-24=3 μg), and combination group(pCDNA3.1-IL-24=3 μg+ As2O3=5μg?mL-1). 48 h later, the following assays were performed. The expression of IL-24 protein in the 4 treatment groups was detected by enzyme-linked immunosorbent assay (ELISA). Single cell gel electrophoresis was used to observe the DNA fragmentation. Micronucleus experiment was carried out to detect the cellular chromosome fracture. Flow cytometry was used to detect the cell apoptosis. Results The ELISA assay results showed that the expression of IL-24 were 12.29±4.39 pg?mL-1, 13.93±3.69 pg?mL-1, 332.21±53.12 pg?mL-1 and 339.56±62.31 pg?mL-1 in PBS group, As2O3 group, IL-24 group and the combination group respectively. Compared with PBS group, the expression of IL-24 in IL-24 group and the combined group increased significantly, and the difference was statistically significant (P<0.01). Single cell gel electrophoresis and micronucleus test showed that DNA and chromosome damage increased in the combination group, comparing with As2O3 group, the difference was statistically significant (P<0.05). Flow cytometry assay showed that the apoptosis rate (%) in As2O3 group, IL-24 group and combination group enhanced significantly compared with PBS group（23.47±5.15% vs 1.81±0.26%, P＜0.05; 15.06±3.69% vs 1.81±0.26%, P＜0.05; 28.98±5.69% vs 1.81±0.26%, P＜0.05）. Comparing with As2O3 group and IL-24 group, the apoptotic rate of the combination group was much higher, and the difference was statistically significant（23.47±5.15% vs 28.98±5.69%, P＜0.05; 15.06±3.69% vs 28.98±5.69%, P＜0.05）. Conclusion The IL-24 combined with As2O3 had synergistic effect and can further enhance the antitumor effect on renal cancer cell Ketr-3.