Peanut protein prepared by ultrasound pretreatment was hydrolyzed with alkaline, papaya protease, trypsin, pepsin, neutral protease, and flavourzyme using DPPH free radicals scavenging activity as the indicator. The results showed that the optimal enzymes were alkaline and trypsin and the combined ratio was 8∶2. The optimal hydrolysis conditions of multi-enzyme and flavourzyme were investigated by means of response surface methodology -RSM-. The correlation between degree of hydrolysis -DH- and DPPH free radical scavenging rate of hydrolyzed peanut protein isolate was further studied. The optimal hydrolysis condition for antioxidant peptides using multi-enzyme was pH 85, hydrolysis temperature 4936℃, the amount of enzyme 340% -m/m-, and hydrolysis time 20359min.