Using hydrolysis degree of protein as an index, this paper investigated hydrolysis effects and conditions of protein from byproducts in channel catfish with papain, comples protease, flavourzyme, neutral protease and alkali protease with single factor and orthogonal tests. The experimental results showed that the highest hydrolysis degree were comples protease. The optimal hydrolysis degree was achieved at 53.26% with the following conditions: hydrolysis temperature of 55 ℃, hydrolysis time of 4 h, pH 9.0, enzyme concentration 2 500 U/g, the ratio of water to materials 1∶3.