In this study, aluminum oxynitride (AlON) powder was successfully synthesized via two-step carbothermal nitridation method. For this purpose, alumina/polyacrylonitrile nanocomposite was first provided with different ratios of alumina to polyacrylonitrile by two efficient ultrasonic and solvothermal methods. The nanocomposite was subjected to a pyrolysis process at 800°C for 2 hours under a high pure argon atmosphere (99.999%, oxygen less than 2 ppm) to form alumina-carbon core-shell structures. Then, by two-step heating of the alumina-carbon core-shell nanoparticles at 1550°C for 2 hours and immediately heated at 1750 °C for 1 hour in the presence of nitrogen gas, AlON powders were synthesized. The amorphous carbon nanolayers on the Al 2 O 3 nanoparticles could strongly retard the coalescence and growth of Al 2 O 3 nanoparticles during the carbothermal nitridation process. As a result, the formation temperature and particle size of AlON powder were significantly reduced. It was found that the sample with a 1:1 ratio of alumina to polyacrylonitrile prepared by ultrasonic method, is fully compatible with the AlON phase. Finally, for characterization of the product (AlON powder), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used.