Abstract: In this study, sunflower meal protein powder was used as raw material to get the best process of preparing antioxidant activity polypeptide by dual enzymatic hydrolysis. Sunflower meal protein were enzymatic hydrolysised by alkaline protease and other six kinds of protease, and the degree of hydrolysis and antioxidant were as indexes to screen enzyme. Antioxidant activity was investigated to optimum enzymatic process through single factor and response surface method. The results showed that the optimal enzymatic hydrolysis conditions which used alkaline protease and papain were as followed : p H7.6, enzyme ratio 2.5∶1, substrate concentration 2%, E/S2%, temperature 50℃, time 200 min, under this condition, the scavenging capacity of sunflower meal polypeptide on the O-2·and ·OH were 68.06% and 50.12%.