Abstract: Squid head protein was hydrolyzed with Flavourzyme 500MG protease for its more comprehensive use. The degree of hydrolysis ( DH) were investigated to estimate the hydrolysis effect.On the basis of single factor tests, the optimal hydrolysis conditions were determined by orthogonal experiments through investigating the DH and superoxide radical scavenging capacity.The results indicated that the optimal conditions of preparing the squid head protein hydrolysates with high DH and strong antioxidant capacity were as follows: the hydrolysis temperature 43℃, hydrolysis time 7h, Flavourzyme 500MG protease dose 800U/g and ratio of material to water 1∶3. Under such conditions, the DH was 43.93% and the superoxide radical scavenging capacity of the hydrolysate was 52.31%.