The invention discloses a method for regenerating a dental prosthetic material and an acidic amino acid-induced demineralized dental enamel outer enamel prism thereof in situ, and belongs to the technical field of in-situ regeneration of dental enamel outer enamel prisms. The preparation method is as follows: firstly, carrying out surface calcium activation onto a dental enamel surface, i.e., grafting calcium ions; then, forming calcium carbonate stable calcium ions step by step; finally, taking calcium carbonate stable calcium ions as foundation forms to synthesize hydroxyapatite crystals. Amino acid participates in the whole process, concentration of the amino acid added in a two-step process is consistent. The hydroxyapatite crystals deposited on the surface of the demineralized dental enamel are orderly and compact in sequence, and uniform in crystal morphology, so that obvious continued growth tendency of an artificial layer can be seen. The preparation method disclosed by the invention lowers protein extracting cost and harsh restrictions on an application environment, and is wide in prospect. The material prepared by the method disclosed by the invention can be applied to cosmetic dental for filling demineralization gaps, also can be used for repairing early-stage enamel demineralization, and can be used as a combined material for bottom pulp capping pit and fissure sealing, and the like.