Abstract: Nanopowders synthesized by a co-precipitation method were modified by spray drying and spherical particles were prepared for transparent ceramics of yttrium aluminum garnet.The phases of the powders were analyzed by X-ray diffraction(XRD);the shape, size and agglomeration of the powders before modification were studied by transmission electron microscopy(TEM);the shape, size and dispersion of the powders before and after modification were characterized and the surface morphology of polished ceramics after hot corrosion was also observed by scanning electron microscopy(SEM).The results show that the PVB addition of 1.0% is the best;the density of molding samples by the modified powders increases significantly, thus influencing the density of the ceramic and the morphology of grain boundaries;using the vacuum sintering technology, the density of the ceramic is up to 99.95%, the average grain size is about 10 μm, the size distribution is more uniform, the grains and boundaries are clean, the impurities and porosity do not exist.