To explore the effects of tetrahydroxystilbene-2-O-β-D-glucoside(TSG) on the apoptosis of HUVEC cells and its mechanisms induced by H₂O₂. The models of apoptosis induced by H₂O₂ in HUVEC and the concentrations of TSG on apoptosis model were established via MTT, Hoechst33258 staining, and Flow Cytometry. The expression of Caspase-3 and PARP was detected by RT-PCR and Western blot. Compared with control group, the viability of cells is decreased and the apoptosis ratios is increased with increased concentration of H₂O₂(P < 0.01) respectively. And the group of 300 μmol/L H₂O₂ inhibited the cell proliferation, increased the number of apoptotic cells significantly. The viability of cells is increased and the apoptosis of HUVECs is decreased after pretreated with different concentration of TSG. According to the MTT and Flow Cytometry, the optimal concentration for H₂O₂ to establish apoptosis model and for TSG to protect HUVECs induced by H₂O₂ were 300 μmol/L and 10 μmol/L respectively. Compared with the control group, the group of 300 μmol/L H₂O₂ inhibited the cell proliferation, increased the number of apoptotic cells and the expression of Caspase-3 significantly. Compared with H₂O₂ group, 10 μmol/L of TSG improved the rate of cell proliferation, inhibited cell apoptosis, and decreased the expressions of the Caspase-3 and PARP significantly (P < 0.01). These results indicate that TSG can inhibit H₂O₂-induced apoptosis of human umbilical vein endothelial cells, and its mechanism may relate to the down-regulation of Caspase-3 and PARP expression.