The invention provides nitrogen-doped spherical porous carbon and a preparation method and application thereof. The preparation method comprises the steps that coal liquefied asphalt is sulfonated andhydrated in sequence to obtain soluble sulfonated asphalt; the soluble sulfonated asphalt, water and imidazolium cation type ionic liquid are mixed to obtain a mixed solution, wherein the imidazoliumcation type ionic liquid is imidazolium cation bromide salt or chlorine salt; the mixed solution is spray-dried to obtain spherical asphalt particles; under the protection of nitrogen or an inert gas, the spherical asphalt particles are carbonized and activated in sequence to obtain the nitrogen-doped spherical porous carbon. The nitrogen-doped spherical porous carbon prepared by using the imidazolium cation bromide salt or chloride salt has a higher nitrogen content; the preparation technology adopting a spray drying technology has the advantages that the steps are simple, the continuous operability is strong, the production efficiency is high, the conglomeration rate is high, the sphericility degree is higher, and the particle size of the microspheres is adjustable, therefore the spheroidization process can increase the yield and specific surface area of the porous carbon.