Abstract: This study optimized polypeptides extraction conditions of sea cucumber (Apostichopus japonicus) gonads from south of China. And the antioxidant activity of sea cucumber gonads polypeptides from south and north of China were compared. Protamex was used to hydrolyze the sea cucumber gonads. Taking the yield of enzymatic peptide as the index, the main influencing factor experiments such as hydrolysis temperature, substrate concentration, pH, time, enzyme dosage and response surface methodology, the enzymatic condition was selected. The above five factors were optimized by response surface methodology on the basis of single factor experiment. The results showed that the optimum conditions were as follows:temperature of 56℃, substrate concentration of 11.5%, enzyme dosage of 0.5 mKat/g, pH of 7.1, enzymolysis time of 4.5 h. The peptide yield was 67.97%±0.96% in this condition, which was 0.26% from the prediction model. The antioxidant activity of gonads polypetide had been measured. The results showed that the superoxide radical clearance and hydroxyl radical clearance of 40 mg/mL Apostichopus japonicas gonad polypeptide solution from south and north of China were greater than 0.1 mg/mL Vitamin C solution, the FRAP value of 60 mg/mL Apostichopus japonicas gonad polypeptide solution from south and north China were greater than 0.1 mg/mL Vitamin C solution. There was no significant difference between these two gonads polypeptides.