Yttrium oxalate carbonate powder was synthesized by hydrothermal reaction using ascorbic acid and yttrium nitrate as reactants. The as-obtained samples were characterized by powder X-ray diffraction (XRD), infrared spectra (IR), thermal analysis (TA), and scanning electron microscopy (SEM). The formation of [Y(H2O)(x)](2)(C2O4)(CO3)(2) could be influenced by the hydrothermal reaction temperature and yttrium nitrate concentration. The morphology of the samples was about 100 mu m powder. According to thermal analysis results, the as-prepared [Y(H2O)(x)](2)(C2O4)(CO3)(2) could first break into Y-2(CO3)(3) and then convert into Y2O3 after annealing at 500-700 degrees C, thus Y2O3 powder of pure phase was obtained and characterized by XRD and SEM. (C) 2015 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.