Abstract： Objective To study the effects of As_2O_3 on tumor model of hepatocarcinoma.Methods HepAgrafed hepatocarcinoma mouse model was established by subcutaneously injection of mouse hepatoma cells(1×10~6)into the oxter of mice.After treated by As_2O_3,the volume change of tumor and tumor inhibition rates were observed.The expression of vascular endothelial growth factor(VEGF) was detected by immunohistochemical and calculated the difference of MVD.Results The volume of tumor and the tumor inhibition rates were significantly decreased in As_2O_3 group compared with control group(P<0.05).The As_2O_3 could inhibit angiogenesis of xenograft tumor,depress expression of VEGF and decrease microvascular density(MVD).Conclusion As_2O_3 can inhibit the growth of tumor,inhibit the expression of VEGF and decrease MVD.