Crystalline alpha-alumina (α-A2O3) powders were prepared by using chemical co-precipitation method with different pH values. Prepared powders were fired at 1300°C in the air for 4 hours. Structural properties of the prepared powders were studiedusing Fouriertransform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX). XRD results confirm that the powders have the α-Al2O3phase with the main peak (113) ofrhombohedral(hexagonal) crystal structure, where the average crystallite size of particles of the prepared samples increasefrom (32-38)nmwith increases of pH value.FTIR results indicatethat the samples contain the molecular functional groups of (Al-O) bondsthatappear in (AlO6) groupof the rhombohedral structure of α-Al2O3with corundum structure whichis built up only in this group,and this result supports the results of XRD.The SEMmeasurements results showed that the powders particles have apparent porosity, agglomerated size, and the size distribution ofparticles is mostly uniform wherethe particle size ranges from (93 to 189)nm.EDXwasused to confirm the chemical analysis of aluminium oxide powders and it showedthat(Al) and (O) are the main components of alumina particles with no impurities, hence,confirmedthe stoichiometric of the prepared alumina powderby the co-precipitation method.