Oysters are the important marine biological resources available to human beings. The oyster shells contain important organic matters, such as amino acids, proteins and peptides. In the present study, the oyster shell peptides (OSP) were prepared, and the in vitro antioxidant activities of OSP were investigated. OSP were obtained by water refluxing extraction, followed by anionexchange chromatography and reverse-phase C8 column chromatography. Using vitamin C as control, the capacity of OSP in scavenging 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), superoxide anion, hydroxyl and 1,1-diphenyl-2-picrylhydrazine (DPPH) radicals was determined. In addition, using disodium ethylenediamine tetraacetate as control, the capacity of OSP in chelating Fe 2+ was determined. Results showed that, OSP had the capacity of scavenging ABTS, superoxide anion, hydroxyl and DPPH radicals and chelating Fe 2+ . In conclusion, OSP have the antioxidant activities, and can be further developed into functional health food or medicine with related activities.