In this study, α-Al2O3 nanoparticles were prepared using a simple sol-gel method. Prepared α-Al2O3 nanoparticles characterized by XRD, FESEM, TEM, and EDS analysis. XRD patterns of the prepared α-Al2O3 nanoparticles showed that the diffraction peaks of 2Ɵ ~ 43.8°, 35.0°, 57.4°, 25.4°, 68.1°, 52.5°, 37.7°, and 66.5°, and results also showed that the nanoparticles have a polycrystalline and a rhombohedral structure. These values exactly agree with the International Center of Diffraction Data (ICDD), card number 00–010–0173 of α-Al2O3. The average crystallite size of the prepared nanoparticles was 33.9, 27.7, and 24 nm that calculated using the Scherrer method, Williamson-Hall analysis, and SSP respectively. FESEM images have shown that crystalline nanoparticles have heterogeneous sizes, different shapes, spherical, and semi-spherical, and particle size distribution was ranged from 15 – 45 nm.