Abstract: The optimum enzymolysis condition of calcium-chelating collagen peptides from blue shark cartilage was investigated by single factor test and orthogonal test. The maximum calcium-chelating ability( 1087.01 mg /100 g protein) was obtained at hydrolysis time of 1 h,enzyme dosage of 0.25% and substrate concentration of 25 mg/m L.In the obtained collagen peptides,about 84% component was distributed with molecular weight below 5000 u,the content of glutamic acid and aspartic acid,and the content of hydrophobic amino acids were 17.07% and 41.24%,respectively.However,the ratio of essential amino acids to total amino acids was 22.81%.Based on results of fourier transform infrared spectroscopy( FTIR) and scanning electron microscope( SEM),it was found that the microstructure of calcium-chelating collagen peptides,which not only had the characteristics of collagen but also contained chondroitin sulfate,was uniform compact.