The invention provides a method for preparing a beluga swimming bladder protein peptide. The method specifically comprises the following steps: treating and shredding fresh beluga swimming bladders, adding 5-fold dilute alkali liquor, soaking for 3 hours, performing centrifugal separation, washing the precipitate until the pH value is neutral; adding a 5-fold dilute acid solution, soaking for 2 hours, performing centrifugal separation, and washing the precipitate until the pH value is neutral; adding 10-fold water, extracting at the temperature of 90 DEG C for 6 hours, and filtering; cooling to 50 DEG C, regulating the pH value to 9, adding 0.5 percent of alkaline protease, performing enzymolysis at the temperature of 50 DEG C for 4 hours, and performing enzyme deactivation at the temperature of 95 DEG C for 5 minutes; cooling to 45 DEG C, regulating the pH value to be 2.5, adding 0.3 percent of acid proteinase, performing enzymolysis at the temperature of 45 DEG C for 5 hours, and performing enzyme deactivation at the temperature of 95 DEG C for 5 minutes; and regulating the pH value to be neutral, filtering, desalting, concentrating, and drying, thereby obtaining the beluga swimming bladder protein peptide.