The invention belongs to the technical field of new materials, and particularly relates to a core-shell moisturizing material, and a preparation method and application thereof. The particle diameter of the core-shell moisturizing material is 80-160 mu m, the shell is a calcium alginate film of which the thickness is 10-50 mu m, and the core is a mixture of an anionic monomer and a nonionic monomer. The preparation method comprises the following steps: neutralizing acrylic acid and/or methacrylic acid with a sodium hydroxide solution; then adding acrylamide and/or hydroxyethyl acrylate; sequentially adding sodium alginate shell-building agent, crosslinking agent and initiator, and uniformly mixing to obtain a reaction solution; finally, dropwisely adding the reaction solution into an oil-water phase, and reacting; and after the reaction is completed, washing, and drying to obtain the product. According to the invention, the shell thickness of the moisturizing microsphere material can be effectively controlled, thereby being capable of controlling the light resistance and moisturizing property of the material after water absorption; and the core-shell moisturizing material can be widely used for water absorption application in the aspects of moisture retention of dry soil, medical health and daily service.