Provided is a sheet-shaped nitrogen-phosphorus co-doped porous carbon material, prepared and obtained according to the following method: mixing aniline and hexachlorocyclotriphosphazene, undergoing a closed reaction for 2-24 h at a pressure of 1-10 MPa and a temperature of 140-260° C., then pressure is released to atmospheric pressure and steam drying is performed to obtain a solid substance; under inert gas protection, the obtained solid substance is treated for 1-6 h at a high temperature of 400-1000° C., and the finished product is obtained; the sheet-shaped nitrogen-phosphorus co-doped porous carbon material thus provided has excellent electrical properties and may be used for fabricating capacitor electrodes and especially supercapacitor electrodes; thus it may be used in capacitors and especially supercapacitors, and has great application potential and industrial value in the field of energy storage.