The invention provides inorganic heat radiation nano-grade material aqueous slurry, a heat radiation material comprising the inorganic heat radiation nano-grade material aqueous slurry, and preparation methods and applications thereof. The inorganic heat radiation nano-grade material aqueous slurry comprises the components comprising, by weight, 10-25 parts of an inorganic heat radiation nano-grade material, 0.5-20 parts of a modifier solution, and 50-100 parts of a solvent. The heat radiation material comprises, by weight, 10-30 parts of the inorganic heat radiation nano-grade material aqueous slurry, 40-80 parts of aqueous high-molecular resin, 20-30 parts of latex, 10-40 parts of a film-forming auxiliary agent, 0.5-5 parts of an auxiliary agent, and 5-20 parts of a diluting agent. With the application of the inorganic heat radiation nano-grade material aqueous slurry, compatibility and system dispersion stability of the inorganic heat radiation nano-grade material and the high-molecular material are improved, such that the unique heat radiation material with excellent heat radiation performance and with the inorganic heat radiation nano-grade material aqueous slurry is obtained.