Experimental parameters for floating nitridation process were examined to study the effect on moving behaviour and direct nitridation characteristics of aluminium powder, which was carried over from a fluidized bed. The conversion increased with increasing reactor temperature and mole ratio of ammonia to aluminium. It was also strongly dependent on the thermal decomposition of ammonia participated in the reaction. Aluminium powder was converted to aluminium nitride as high as 0.90 when the reactor temperature was 1300 degrees C and the mole ratio was 19.5 The particle size and specific surface area of the powder increased with increasing conversion, which was due to the volumetric and structural change of aluminium particles when nitrided to form fine crystallites with higher porosity.