GaN nanopowders were synthesized by ammoniating pure Ga2O3 powders at 1000°C for different soaking time. The results show that the growth of GaN at this temperature is based on vapor-solid mechanism. The ammoniating reaction finished and the rearrangement process started when the soaking time is 0.5 h. When the soaking time is 1.5 h, the process of high-temperature aggradation transformed to thermal decomposition-re-crystallization process. Further increasing of soaking time, the fabricated GaN particles with large size aggregated by directional fixed nanorods are substituted by self-governed particles, which agglomerate as honeycomb. Photolumine- scence measurement (PL) test reveals that as prepared sample with 1.5 h possesses the best luminescent property.