Abstract: Using single factor experiments to optimize technology that hot water was used to extract collagen from fish scale. Then, using orthogonal experiments to optimize the enzymolysis technology of collagen peptide that were studied. When extraction temperature of solution was 70℃, extraction time was 6 hours and ratio of material to solvent was 1 ∶20, the optimum extraction process was obtained, and the maximum yield was32.55%. When the pH of solution was 9.5, the temperature of solution was 55℃, the reaction time was 2.0 hours and amount of enzyme was 0.3% (v/v) , the optimum extraction process of collagen enzyme was obtained, and the largest degree of hydrolysis was 23.17%. Automatic amino acid analyzer was used to measure amino acids of collagen polypeptide distribution, its amino acid composition was according with the characteristic of collagen. Gel permeation chromatography was used to determine the molecular mass of collagen peptide, most of the molecular mass of collagen peptide was within 1000 u.