Abstract: Objective 　To study the inhibition effect of VEGF expression in human bladder carcinoma cells by ¹²⁵I-coupled antisense oligonucleotides ( ¹²⁵I-ASODN) . Methods 　VEGF expression in human bladder cancer cells was detected with immunohistochemistry. Endothelial cell growth was assessed after adding conditional medium. Results 　By immunohistochemistry, the positive cells were 89. 1/ 100 cells in control group, 90. 3/ 100 cells in ¹²⁵I-Na group, 10. 3 in ASODN group and 4. 3 in 125 I2ASODN group. The D value of each group was 0. 398 ± 0. 031, 0. 387 ±0. 010, 0. 298 ±0. 013 and 0. 148 ±0. 011. Comparing ¹²⁵I-ASODN group and ASODN group with cont rol and ¹²⁵I-Na group, difference was significant ( P <0. 05) . Conclusion 　¹²⁵I-ASODN can effectively suppress VEGF expression of human bladder cancer cells. It has good prospect in canti-angiogenesis of bladder carcinoma.