The invention discloses donkey milk cosmetic and a preparation method thereof. The donkey milk cosmetic is prepared by evenly mixing and treating multiple ingredients comprising over 30 percent of donkey milk. The added donkey milk serving as a main moisturizing agent, a nutrient, a whitening agent and an anti-ageing activating agent is used for preparing cosmetics such as moisturizing emulsion, skin cream, whitening and moisturizing emulsion, anti-wrinkling and anti-ageing nutrient essential milk, cleaning milk, bath foam, shampoo, hair conditioner, mask, soap and the like to promote metabolism of the skin, enhance blood circulation, improve the hydration degree of the skin, moisture the skin with elasticity, and recover the luster of the skin. The donkey milk cosmetic has the function ofrepair and activation, has better natural moisturizing and compacting functions on the skin, can inhibit the increment of pigment and thin freckles, has whitening effect, can reduce pores, regulate skin texture and promote the metabolism of skin epidermis cells, and has the function of delaying skin ageing. The donkey milk cosmetic serving as a unique and novel advanced skin-care product has strong physiological activity and remarkable efficacy.