Objective To explore the protective effects of trimetazidine on vascular endothelial cells injury induced by hydrogen peroxide (H2O2) and its pharmacological mechanisms of anti-oxidation. Methods Human umbilical vein endothelial cells (HUVECs) were injured by H2O2. Next, the cells were treated with three different concentrations of trimetazidine (1μmol/L,10μmol/L,100μmol/L, respectively). The viability of cells was detected by methyl thiazoeyl tetrazolium (MTT) assay. In addition, malondialdehyde (MDA) contents, superoxide dismutase (SOD) and secretion of NO were measured. Results Trimetazidine could enhance the viability of the injured HUVECs induced by oxidation, decrease the level of MDA, enhance the SOD activity, and increase the secretion of nitrogen monoxide. These effects were in a certain dose-dependent manner and the difference was significant among the three concentrations (P<0.05). Conclusions Our results suggest that trimetazidine may protect lipid peroxidation and prevent oxidation-induced cellular dysfunction of HUVECs.