Three kinds of industrial proteases were applied to investigate the effect of hydrolysis process on the functional properties of crass carp(Ctenopharyngodon idellus) scale derived collagen peptide.The results revealed that collagen peptide with different DH and the same DH by different proteases showed different properties.For alcalase 2.4L FG group,after 4 h of hydrolysis,the clearance of DPPH free redical,emulsifying activity index (EAI) and DH were 82.14%,70.12 m2/g and 9.5%,respectively.For protamex group and neutrase 1.5 MG group,after 4 h of hydrolysis,the DH of collagen peptide were 8.7% and 7.2%,the clearance of DPPH free redical were 86.32% and 70.15%,and the EAI were 32.93 m2/g and 36.88 m2/g,respectively.