Abstract: Objective: To observe the effect of As₂O₃ on cryoablation in a VX2 tumor model and the corresponding changes of CT perfusion. Methods: A total of 30 New Zealand white rabbits were successfully implanted with VX2 tumor in liver and randomly divided into two groups, the experimental group was injected with As₂O₃, the control group was injected with salt water. CT perfusion was performed to calculate blood flow (BF), blood volume (BV), and to observe the effect of As₂O₃ on tumor blood flow and cryoablation. Results: 1) The mean largest diameter of cryoablation was 1.6± 0.4cm in the experi-mental group and 0.9± 0.3cm in the control group (t=5.4, P<0.05); 2) Before cryoablation, the values of BF and BV were 26.60± 6.41ml/100g·min and 8.42± 3.56ml/100g in the experimental group, and 63.75± 8.29 ml/100g·min and 14.68± 3.42ml/100g in the control group, respectively (P<0.05). Conclusion: As₂O₃ can obviously reduce the tumor blood flow and in-crease the diameter of cryoablation. CT perfusion imaging is capable of quantitative assessment of the changes in blood pa-rameters.