The invention belongs to the technical field of dry masks, in particular to a preparation method of a whitening and moisturizing dry mask. The preparation method specifically comprises the following steps that 1, bamboo leaf fiber, aloe fiber and China rose fiber are cleaned respectively, mixed and crushed, seabuckthorn flavone and an erythritol water solution are added and stirred, the mixture issubjected to vacuum freeze drying, reinforcing is conducted according to an operation process of a conventional spunlace method to prepare a mask, spraying and drying are carried out, and mask paperis obtained; 2, fresh strawberry leaves and fresh spinach are mixed and pulped, water is added, the mixture is sealed, placed and subjected to CO2 supercritical fluid extraction treatment, an extractis obtained, dandelion polysaccharides and portulaca oleracea polysaccharides are added, and magnetization treatment is carried out to obtain essence; 3, the mask paper is soaked in the essence, subjected to vacuum freeze drying and compressed to obtain the whitening and moisturizing dry mask. The mask has strong anti-oxidation performance and free radical removing, moisturizing and moisture retention capacity, so that skin of a user is smooth, tender, white, ruddy and glossy, the antibacterial property and the antiallergic ability of the skin are enhanced, and the skin health is promoted.