By water soluble preparation of oligo peptide of fermented bean curd, physico-chemical analysis and amino acid composition analysis, through and ascorbic acid comparison ·OH, DPPH·, O-₂· free radical scavenging capacity, evaluation of fermented bean curd oligopeptides antioxidant activity of the oligopeptides. The results showed that the total protein content of fermented bean curd oligopeptides 85.47%. The amino acid composition of the rich, rich in antioxidant amino acids must amino acid content of 34.43%, with the total amino acid content of antioxidant activity was 30.5%; antioxidation experiment results show, fermented bean curd oligopeptides with free radical scavenging capacity and of ·OH, DPPH·, O-₂· free radical half inhibitory concentration (IC₅₀) was 5.8, 6.1, 9.7 mg/mL respectively. Therefore, oligo peptide has strong antioxidant activity in pickled tofu.