Glutathione peroxidase is a mammalian selenoenzyme that catalyzes the reduction of hydroperoxides and play crucial roles in scavenging reactive oxygen species in living organisms. Native glutathione peroxidase have poor solubility and limited cellular accessibility. Morevoer, it is difficult to prepare using traditional recombinant DNA technology. Peptides with an Arg-Gly-Asp (RGD) sequence have shown to have a high affinity for cytomembrane. In the present study, a novel selenopeptide, Sec-RGD, was designed and synthesized. Moreover, its antioxidant was confirmed by cytological expeniments.