Abstract: With Bay scallop and Japanese scallop as raw material, effects of species of scallop and enzyme, enzyme quantity, temperature and the ratio of solid to liquid on the degree of hydrolysis (DH) and free radical scavenging activity were studied. On the basis of single factor experiment, orthogonal experiment of L9 (34) was used to optimize the technical parameters. Results indicated that the optimal hydrolytic conditions were as follows:using Bay scallop as the material, enzyme quantity of the neutral protease 3.25% (E/S) , temperature40℃, the ratio of solid to liquid 1 ∶2.5. The DH was 45.91%, and the scavenging rate of DPPH radical and superoxide anion radical were 91.90% and 79.72%.