Abstract: Using the YCl₃and oxalic acid as raw materials, effect of microwave on morphology of synthesis Y₂O₃ precursor in the liquid phase are investigated. The effects of mole ratio of H₂C₂O₄ to YCl₃, initial concentrations of YCl₃, reaction time and reaction temperature on the morphology and the dispersion of precursor were investigated. By using means of techniques such as scanning electron microscope (SEM), X-Ray Diffraction (XRD) and TG-DTA to precursors and thermal decomposition products are characterized. The results showed that the large particle size and sand shape precursor with the average particle size of about 40 μm was produced under the conditions: mole ratio of H₂C₂O₄ to YCl₃ is 2:1, initial concentration of YCl₃ is 0.5 mol/L, reaction temperature is 40 ℃ and 3 h reaction time.