A method of preparing a sturgeon skin gelatin with antioxidant activity includes: 1) soaking sturgeon skin in water, and sonicating the sturgeon skin; 2) cutting the sturgeon skin, soaking the sturgeon skin in a NaOH solution, and soaking the sturgeon skin in an HCl solution; 3) washing the sturgeon skin of step 2) to neutral, placing the sturgeon skin in an extraction solution for extracting sturgeon skin protein; and 4) obtaining the sturgeon skin gelatin. A method of preparing a sturgeon skin gelatin film includes: 1) dissolving sturgeon skin gelatin in water to obtain a sturgeon skin gelatin solution; 2) adding glycerine to the sturgeon skin gelatin solution; and 3) obtaining the sturgeon skin gelatin film.