Abstract: The enzymatic hydrolysis action of protein in silver carp by different proteases was investigated. The nitrogen yield, degree of hydrolysis and average length of peptide chain were studied on enzymatic hydrolysate. Results showed that Alcalase was the best that had higher nitrogen yield, degree of hydrolysis and average length of peptide chain. The optimum enzymatic conditions for Alcalase hydrolysis were that hydrolyzing at 55℃, adding 2000U/g, pH7.5 and feed ratio of 1∶4. The average lengths of peptide chain, degree of hydrolysis, nitrogen yield were 3.87, 24.12% and 91.85% respectively after hydrolysis of 3h.