The invention discloses a nitrogen-doped graphene/silicon carbide microsphere nanometer composite material as well as a preparation method and application thereof. The nitrogen-doped graphene/silicon carbide microsphere nanometer composite material comprises silicon carbide microspheres and nitrogen-doped graphene growing on the surfaces of the silicon carbide microspheres. The preparation method comprises the following steps: by taking a graphite flake or a silicon chip as a growth substrate, performing high-temperature pyrolysis on liquid polysilane in an inert atmosphere, performing strong oxidative acid activation and hydrazine hydrate reduction, thereby obtaining the product; or by taking a graphite flake or a silicon chip as a growth substrate, performing high-temperature pyrolysis on a mixture of liquid polysilane and a liquid state nitrogen-containing hydrocarbon in the inert atmosphere, thereby obtaining the product. The nitrogen-doped graphene/silicon carbide microsphere nanometer composite material disclosed by the invention has the advantages of aggregation resistance, corrosion resistance, high catalytic activity and repeated recycling, the preparation method is simple and convenient, and the composite material can be widely applied to the field of high-effect selective organic catalytic reactions.