The invention relates to a sodium alginate film containing vitamin E and a preparation method thereof. According to the invention, the sodium alginate film is obtained by using sodium alginate and polyvinylidene as structure carriers, functionalizing vitamin E and carrying out freeze-drying molding. The preparation method comprises the following steps: mixing sodium alginate and a vitamin E solution and stirring to emulsify; dissolving PVA in water of 75-85 DEG C, and filtering to obtain a PVA aqueous solution; adding the PVA aqueous solution into an emulsion of sodium alginate and vitamin E, stirring, and pouring into a mold; placing the mold into an environment of minus 35-10 DEGC to obtain a freeze-dried film in the mold; and taking out the freeze-fried film out, adding the freeze-fried film into an ethanol-water mixed liquor of CaCl2, immersing, washing with deionized water and drying to obtain the sodium alginate film. The preparation method is simple to operate and has high efficiency. The sodium alginate film has characteristics of porous structure, good elasticity, good flexibility, high water content, oxidation resistance, ultraviolet radiation resistance, wound treatment, skin maintenance and the like.