Abstract: The extraction process of glycosaminoglycan from swim bladder via enzymatic hydrolysis by pancreatin and neutral protease of Bacillus subtilis were optimized by response surface methodology based on single factor experiments, the physic-chemical characters and structure properties were analyzed by UV and IR spectroscopy, and the evaluation of the capacities of hygroscopicity and moisture retention were conducted in this investigation. The results showed that the optimum processing conditions of enzyme hydrolysis was solid-liquid ration of 1 ∶ 20 g ∶ m L, enzymolysis time of 4 h, enzymolysis temperature of50 ℃, enzyme dosage of 7%, and the enzmolysis p H of 8.0. Under these optimum conditions, the yield and content of glycosaminoglycan were of 1.19%, 19.09%.Moreover, the IR spectrum showed that the extracted glycosaminoglycan had typical characteristic absroption peaks of polysaccride, and comprised a pyranose ring structure having an α glycosidic bond.Finally, the extracted glycosaminoglycan had excellent capacities of hygroscopicity and moisture retention, which were superior to those of the conventional humectants, such as chitosan and sodium alginate. These results clearly established the possibility that swim bladder glycosaminoglycan could be effectively employed as a moisturizer.