A new preparation method for a highly sinterable Y2O3 powder was developed, using the mixture of the powder with Al2O3 powder, a transparent yttrium aluminum garnet(YAG) ceramic was prepared at relatively low temperature by a solid-state reaction method. Yttrium nitrate was used as a mother salt, and aqueous ammonia was used as a precipitant reagent, the fine and dendritic precursor crystalline was prepared by adding 0.5% ammonium sulfate into the precipitation reaction system. The highly pure and low-agglomerated Y2O3 powders were obtained by calcinating the precursor at 1 100 ℃, the primary particles are spherical and 60 nm in diameter. The mixture of Y2O3 and Al2O3 powders was calcinated, and the resulting mixture compact pressed in mold could be sintered to transparency under vacuum at 1 700 ℃. The sintered transparent YAG polycrystalline exhibits a homogeneous microstructure and its transmittance reaches 45% in the visible light region and 70% in the near-infrared wavelength region.