Objective To investigate the effect and mechanism of Complex Xueshuantong on the angiogenesis of rhesus choroid-retina endothelial (RF/6A) cells. Methods This experimental research included 4 parts. ①RF/6A cells in logarithmic growth phase were cultured and divided into blank control group, positive control group (0.20 mg/ml protamine) and Complex Xueshuantong groups at different concentrations (0.39 to 50.00 mg/ml). Vascular endothelial growth factor (VEGF) at terminal concentration of 10 ng/ml was added into all groups. The optic absorptions (A values) of each group were measured 24 hours later. ②RF/6A cells in logarithmic growth phase were cultured in Transwell insert and divided into blank control group, Complex Xueshuantong groups at different concentrations of 3.13, 6.25, 12.50 mg/ml. The number of cells that migrated to under the Transwell membrane was counted after cultured for 24 hours. ③RF/6A cells were divided into blank control group, Complex Xueshuantong groups at different concentrations of 0.39, 0.78, 1.56 mg/ml. The number of full-formed tubes was counted after cultured for 12 hours. ④RF/6A cells were divided into blank control group, positive control group of protamine at terminal concentration of 0.20 mg/ml, and Complex Xueshuantong groups at different concentrations of 1.56, 3.13, 6.25 mg/ml. Western Blot and real-time quantitative RT-PCR were used to detect the expression of VEGF and matrix metalloproteinase 2 (MMP-2) protein and mRNA of RF/6A cells after cultured for 24 hours. Data were statistically analyzed by ANOVA method. Results ①The difference of the A values within groups was statistically significant (F=158.669, P＜0.01). Compared with that of blank control group,the A values of Complex Xueshuantong groups at different concentrations from 0.78 to 25.00 mg/ml were significantly reduced (all P＜0.01), the proliferation of RF/6A cells induced by VEGF was inhibited by Complex Xueshuantong at certain concentrations. ②When the concentrations of Complex Xueshuantong were 0, 3.13, 6.25, and 12