The polypeptide was prepared from the Sardinops sagax by the combination hydrolysis by animal proteolytic enzymes and flavor enzyme， then separated by ultrafiltration membrane. The peptides of different molecular weight range were F1（100-3 000 u）， F2（3 000-10 000 u） and F3（≥10 000 u）. The antioxidant activity of each component was determined by DPPH， ABTS and hydroxyl free radical scavenging ability. The results showed that the antioxidant activity of component F1 was the strongest. Using ABTS free radical scavenging capacity as screening indexes， two antioxidant peptides coded b-f1 and b-f6 were separated and purified by the strong anion and YMC-pack-OSD-AQ. The sequences of these peptide were identified by ESI MS/MS as follow. The sequence of antioxidant peptide b-f1 was Arg-Phe-Asp （RFD）/Trp-Thr-Met （WTM） with molecular mass of 436 u， and the sequence of antioxidant peptide b-f6 was Phe-Ala-His-Asp-Asp-Pro with molecular mass of 700 u. The ABTS free radical scavenging capacity of b-f1 and b-f6 were （81.22±4.12）%， （76.35±3.32）%， respectively.