Spherical monodispersed, submicron-sized Y2O3 powder was prepared via a homogeneous precipitation method using nitrate and urea as raw materials. The structure, phase evolution and morphology of Y2O3 precursor and the calcined powder were studied by FTIR, TG/DTA, XRD and SEM methods. The sphere size of the precursor was about 250 nm and that of Y2O3 powder calcined at 800 degrees C for 2 h was about 200-210 nm. With the spherical Y2O3 powder and a commercial Al2O3 ultrafine powder, high transparent YAG ceramics was fabricated by vacuum sintering at 1780 degrees C for 6 h through a solid-state reaction method. The in-line transmittances of the as-fabricated YAG ceramics at the wavelength of 1064 nm and 400 nm were 82.8% and 79.5%, respectively, which were much higher than that of the YAG ceramics with a commercial Y2O3 powder and a commercial Al2O3 ultrafine powder directly. The superior properties are attributed to the good morphology, dispersibility and uniform grain size of the as-prepared spherical Y2O3 powder, which matches that of the commercial Al2O3 powder. (C) 2010 Elsevier Ltd. All rights reserved.