A method for synthesizing aluminum nitride is disclosed, wherein an ignition agent is formed by mixing an azide powder (such as sodium azide; NaN.sub.3) and aluminum powder, and is paved on an ignition portion of a reactant-containing body having a plurality of ratios of aluminum to a diluent, wherein the content of the diluent is gradually increased in accordance with the propagation direction of combustion wave generated in the combustion synthesis process. The method for synthesizing aluminum nitride is to ignite the ignition agent located in the ignition portion of the reactant-containing body under an ambience in which the pressure is less than 1 atm, and to introduce nitrogen gas as the nitrogen source into the reaction chamber after ignition.