Abstract: The response surface methodology ( RSM) was conducted to ascertain the optimum hydrolysis parameters of grass carp muscle.Hydrolysis conditions ( viz., ratio of solvent to solid, initial pH, temperature, ratio of enzyme to substrate concentration ( E/S) , hydrolysis time) were studied to determine the optimal value of the single factor experiment.On the basis of the experimental result, response surface experiment was designed, and the mathematical model of the hydrolysis degree was established. The results showed that the optimum conditions were determined to be ratio of solvent to solid 4mL /g, initial pH6.75, temperature 50℃, E/S 18.5LAPU /g, hydrolysis time 7.8h.Under the condition, the hydrolysis degree ( DH) of grass carp muscle was 49.76% and almost reached the model calculation value 49.94%, which showed that the model could be used to predict calculation. The significant factors on the DH were E/S and hydrolysis time.