Abstract: Flavor protease was chosen to prepare ACE inhibitory peptides from channel catfish (Ictalurus punctatus) skin gelatin.Five process conditions affecting ACE inhibitory activities of gelatin hydrolysates, such as temperature, pH, concentration of substrate, the amount of enzyme and hydrolysis time that were determined by single factor experiment.According to this, Box-Behnken experimental design combined with response surface methodology was taken to optimize the hydrolysis conditions for production of ACE inhibitory peptides from channel catfish skin gelatin.The result showed that the optimal hydrolyzing conditions of flavor protease for production of ACE inhibitory peptides were temperature 50℃, pH 7.0, concentration of substrate 4.5%, the amount of enzyme 2.5%, and hydrolysis time 3h.The ACE inhibitory activity of obtained gelatin hydrolysates at this condition could reach 91.45%, and that of verification result was 89.81%.