Abstract: The extraction technology of collagen peptides from acaudina molpadioides was studied in this article. The non-collagen protein of acaudina molpadioides was separated by sodium chloride solution, using single factor experiment to validate the optimal conditions of sodium chloride solution including the concentration of 9%, 10 times volume of the quality of acaudina molpadioides, marinated for 24h. Under these terms, the proportion of separated non-collagen protein in the total protein accounted for 11.5%. Based on single enzyme factor experiment, AS.1398 neutral protease was selected to hydrolyze collagen protein of acaudina molpadioides. Considering the moisture-absorption and moisture-retention, orthogonal experiment was conducted to optimize the preparation of the collagen peptides from acaudina molpadioides, with the results of the solid/liquid ratio 1:2, temperature 40℃, amount of added enzyme 2400 U/g, pH 7.5, and reacting time 3h, the moisture absorbency and moisture-retention ability achieved to 6.11% and 81.23%, respectively.