Abstract: Gastrointestinal tract digestion system was simulated,in which endogenous protease from shrimp head was used to obtain short peptides by degrading protein in shrimp head.The results demonstrated that the release amount of shrimp head protein,the degree of hydrolysis and the proportion of the components under 3000 u in the hydrolysate showed all significantly increase twice during the process of simulated digestion,which meant that endogenous pepsin- like protease and trypsin- like protease worked in different stages of simulated digestion process,respectively.In simulated gastric digestion process,the molecular weight of the autolysis in shrimp head mainly focused on 2000 ~ 3000 u,and in simulated intestinal digestion process it focused on 1000 u or less.The results suggested that short peptides with high added values can be obtained by using endogenous proteases in shrimp head to simulate gastrointestinal digestion and in this way,proteins in shrimp head can be retrieved efficiently.