Abstract: Antler peptides with different molecular weight cutoff were prepared by membrane technology and their antioxidant activities were evaluated by five kinds of methods. The results indicated that the antioxidant activity of peptide III was the best, and its molecular weight was less than 6214 u. The ability of O-2·free radical scavenging and the reducing of the peptide III were weaker than that of VCwhen their concentration was in the range of0.1~10.0mg / m L, and the ability of DPPH· free radical scavenging of the peptide III was the same as VCwhen their concentration was 10.0mg / m L.But the ability of hydroxyl radicals scavenging and the liposome oxidation inhibition of the peptide III were higher than that of VCwhen their concentration was in the range of 8.0~10.0mg / m L.