This study focuses on the chicken protein hydrolyzed by papain to explore optimum technical conditions of hydrolyzing,changes in content of free amino acids(FFA) and distribution of molecular weight of peptides during hydrolysis.The results indicated that the optimum technical conditions of chicken hydrolysis by proteinase were as follows: 6.0% of enzyme was added at 45℃ to react for 6h with the liquid solid ratio of 2∶ 1 and the initial pH value of 6.5.The hydrolysate was found to be abundant in FFA.The content of FFA increased in the first 16h,and then was nearly remained unchanged after that.Peptide molecular weight of hydrolysate was less than 3000 Da.Polypeptides were gradually degraded during the hydrolysis.The content of peptides and amino acids with molecular weight under 1000 Da reached 97.19% after 24 h of hydrolysis.