The optimal enzymolysis processing for Onchidium struma muscle protein extraction by trypsin was investigated by response surface methodology and orthogonal design on the basis on the basis of single factor. The results showed that the optimum enzymolysis processing conditions via response surface methodology were as followed: enzymolysis temperature 45 ℃, enzymolysis time 2.3 h, pH value 9.0 and liquid-solid rate 92︰1(V︰m). And by the Orthogonal design, were enzymolysis temperature 45 ℃, enzymolysis time 2 h, pH value 9.0 and liquid-solid rate 90︰1(V︰m). The extraction protein rates by these of two methods were 8.74% and 8.52% respectively.