Disclosed is a method for protecting aluminum nitride from moisture. At first, a mixing apparatus is provided. Aluminum nitride powder, calcium silicate, dodecylamine, a binding agent and an anhydrous solvent are mixed with one another by the mixing apparatus. The mixture is made into grains in a granulating process. The hydrophilism, thermal stability and thermal conductivity of the dodecylamine are used to make the grains moisture-proof and not vulnerable to deterioration. Thus, the stability of the aluminum nitride is improved.