The invention discloses a preparation method of a nitrogen-doped porous carbon foam material and application of the nitrogen-doped porous carbon foam material in a metal-air battery. The preparation method comprises the following steps of carrying out concentrated sulfuric treatment on an organic matter containing nitrogen and oxygen, and freeze drying to obtain a precursor; putting the precursor into a protective atmosphere, warming and carbonizing to obtain the nitrogen-doped porous carbon foam material with a porous foam structure, a large specific surface area, uniformity in nitrogen doping, a favorable mechanical property and a favorable electrochemical property. According to the application of the nitrogen-doped porous carbon foam material used as a catalyst in the metal-air battery, the nitrogen-doped porous carbon foam material has excellent catalytic performance, the air electrode polarization can be effectively reduced, and the discharge performance of the air battery is improved.