As one of the most important antioxidant enzymes, glutathione peroxidase(GPX) protects cells and tissues from oxidative damage, and plays an important role in cardiovascular and cerebrovascular injuries induced by oxida- tive stress. The antioxidant effect of selenium-containing glutathione S-transferase(Se-GST), a mimic of GPX was investigated on rat cardiomyocytes. To explore the protection function of Se-GST in hydrogen peroxide(H202) chal- lenged rat cardiomyocytes, we examined malondialdehyde(MDA), lactate dehydrogenase(LDH), superoxide dismu- tase(SOD) and cell apoptosis. The results demonstrate exposure of rat cardiomyocytes to H202 for 6 and 12 h induced the significant increases of MDA, LDH and apoptosis rate of cardiomyocytes, but pretreatment of rat cardiomyocytes with Se-GST at 0.0005 or 0.001 unit/mL prevents oxidative stress induced by H202 with the decreases of cell apopto- sis. All the results hint Se-GST has antioxidant activity for oxidative stress challenged rat cardiomyocvtes.