Enzymatic hydrolysis of protein from small yellow croaker (Pseudosciaena polyactis) was investigated. Three commercial food grade proteases were used to hydrolyze the small yellow croaker. Among the three hydrolysates, papain hydrolysate exerted the highest scavenging activity against a,a-diphenyl-b-picrylhydrazyl (DPPH) for use in the small yellow croaker hydrolysis. The optimum parameters for hydrolysis using papain were established by the single-factor and orthogonal test. The optimal hydrolysis conditions were as follows: temperature of 60C, hydrolysis time of 4 h, enzyme concentration of 0.2% and meal/water ratio of 1:5. Under these conditions, the highest degree of hydrolysis (DH) was 49.50%. Antioxidants of protein hydrolysates at 40.96, 43.75, 48.85 and 49.50% of DH were further investigated by DPPH and hydroxyl radical-scavenging activity. There is a linear parallel relationship between the DHs and the antioxidant properties, and the DH at 49.50% possessed the highest antioxidant activity. The enzymatic hydrolysis of protein from small yellow croaker could be used to produce the hydrolysates possessing antioxidative activities.