The enzymatic hydrolysis of grass carp by protease was carried out to study the functional properties of the hydrolyzate and the volatile flavor compounds of the hydrolyzate. The results showed that the solubilities and thermal stability of the protease and trypsin were better than those of the pepsin hydrolyzate (P<0.05). After enzyme treatment, the percentage of fresh sweet amino acids in the enzymatic hydrolyzate  increased, and the bitter amino acids  decreased. 83 types of volatile compounds were detected by SPMEGCMS, respectively, and aldehydes, ketones and alcohols were the main compounds present. After enzymatic hydrolysis, the relative content of alcohols was reduced, while the aldehyde and ketone content  increased significantly, the hydrolyzate has an unique flavor. After enzymatic hydrolysis of trypsin,proteolytic enzymes and enzymolysis of grass carp can be used as a food base in processing.