Effect of amino acid composition in collagen peptides on the intestinal adsorption in Mice was investigated. Collagen peptides (CP_O), with mean MW 1kDa, were treated using cation and anion exchange chromatography respectively, and the eluted peptides were named as CP_C and CP_A respectively. The amino acid compositions in CP_C and CP_A were determined. The intestinal absorption of peptides by mice was determined by detecting plasma hydroxyproline (Hyp) and di/tri-peptide after intragastric infusion. The result indicated the Arg and Lys content in CP_C were 12.2% and 7.4% higher than that in CP_O, and the Arg and Lys content CP_A were 18.3% and 26.5% less than that in CP“°C. More Arg/Lys-containing peptides were found in CP_C than that in CP_A by HPLC-MS analysis. The result of animal test indicated that the Hyp content in mice plasma after intragastric infusion of CP_C is 1.39 times higher than that of CP_A. Oligopeptides, Ser-Hyp-Gly, Pro-Hyp-Gly and Leu-Hyp, were found in mice plasma. The plasma concentration of three oligopeptides were 2.1, 1.48 and 1.51 higher after infusion of CP_C compared to CP_A. This research suggests that the amino acid composition is a key factor affecting peptide adsorption in intestine.