The invention relates to the technical field of die steel, in particular to high-strength die steel and a high-strength die steel remanufacturing method. The remanufacturing method comprises the following steps that a plurality of micro-nano grooves are formed in the surface of the high-strength die steel; metal nanoparticles are solidified into the multiple micro-nano grooves, and a transition bottom layer is formed on the surface of the high-strength die steel; iron-base alloy powder is fused on the transition bottom layer to form a fusion covering middle layer; and an outermost protection layer is arranged on the fusion covering middle layer, and at least one of silicon nitride and silicon carbide is contained in the outermost protection layer. According to the remanufacturing method, the high-strength die steel remanufacturing quality can be guaranteed, the high-strength die steel can be used in serious working environment, and the application scope of the high-strength die steel is enlarged; in addition, the remanufacturing cost of the high-strength die steel can be reduced, energy consumption is reduced, and the production efficiency is improved; and the corrosion resistancecan be improved, the material residual stress and brittleness are reduced, and the service life of the die steel under various working conditions is prolonged.