Abstract： Objective To investigate the effect of arsenic trioxide on expression VEGF of lymphoma cells. Methods The VEGF mRNA expression was analysed by by Real-time PCR, and VEGF protein expression in Raji and Jurkat lymphoma cell lines by ELISA. Results ATO can inhibit lymphoma cells by inducing apoptosis. ATO induced lymphoma cell apoptosis was due to time.With the period of ATO effecting on cells goes, the expression of VEGF mRNA and the protein were down-regulated significantly (after 24, 48, 72 h). There were, the VEGF mRNA △△Ct data of treated with ATO, at 12 h, for Raji: 0.75±0.15, 72 h, Jurkat: 1.67±0.13. After 72 h, Raji: 8.95±0.38; Jurkat: 9.09±0.16 (f =3.54, P <0.01; t =3.65, P <0.01). And about the VEGF protein, at 12 h, Raji: 198.38±4.37; Jurkat: 563.11±3.81. After 72 h, Raji: 23.55±2.06; Jurkat: 57.11 ±3.88 (t =2.48, P <0.05; t =2.59, P <0.05). Conclusion ATO can inhibit the proliferation of lymphoma cells by down-regulating the expression of VEGF mRNA and its protein.