The invention discloses a composite electromagnetic shielding paint based on a nano carbon material. The composite electromagnetic shielding paint is prepared by mixing composite shielding materials such as nano carbon particles, nano graphene, carbon nanotube, carbon fiber, ferriferrous oxide particles, iron and nickel carbonyl particles with a polymer emulsion, a coupling agent, a dispersant, an antifoaming agent, a film forming auxiliary agent, a thickening agent and the like. The employed electromagnetic shielding paint has the advantages of low density and wide absorption band, and can be widely used in electromagnetic shielding engineering, and thereby, electromagnetic wave can be shielded and absorbed, electromagnetic interference is reduced, and electromagnetic environment pollution can be avoided.