The invention belongs to the technical field of fireproof door materials, and particularly relates to a fireproof door core veneer formed through rapid autoclaved curing and a preparation method thereof. The fireproof door core veneer is prepared from the following raw materials: water, a cement additive, nano silica sol, a waterproof agent, short fibers, fly ash, gypsum powder, active slag powder, ground calcium carbonate powder, Portland cement and a water-based composite foaming agent. Directional high-temperature and high-pressure curing of the fireproof door core plate is achieved throughthe autoclaved curing forming procedure. A product which has the advantages of the light weight, high strength, heat insulation, the stable volume, excellent water resistance, low water content, lowwater absorption, the low mass loss rate, high heat resistance, good heat stability, excellent carbonization resistance, metal protection function, safety, environmental protection and A-grade fireproof performance is formed; and the whole process flow time of the product from burdening production to terminal qualified products is less than 48 hours, the production efficiency is high, and the comprehensive cost is low.