Traditionally, syntheses of aluminum nitride (AlN) powders by thermal nitridation approaches are carried out at high temperature for several hours. In this study, high-density hexagonal AlN powders have been synthesized from aluminum powders at a relatively low temperature and short reaction time by the microwave plasma-induced nitridation approach at atmospheric-pressure. The effects of reaction time (15–45min), temperature (660–850°C), content of NH 4 Cl (0–50%) in Al powders, applied power (800–1200W), and inlet hydrogen concentration (0–1%) on the characteristics of the synthesized AlN powders are discussed. The results show that the active N-containing species produced from the NH 4 Cl and N 2 accelerated the nitridation process, the addition of NH 4 Cl inhibited the aggregation of powders, and inlet hydrogen reduced the residual oxygen, resulting in wurtzite AlN powders with fine particles and nanowires within porous microstructures after a relatively short time (15min), at low temperature (800°C), and with the content of NH 4 Cl=50%, and H 2 =1%.