New laser materials have been explored continuously due to the long growth time and high cost of the crystals. Transparent ceramic is one of the latest developed laser materials. In this paper, polycrystalline Nd3+:Gd3Ga5O12 (Nd3+:GGG) nanopowders for transparent laser ceramic were synthesized by sol-gel method. The sample crystalline phase and shapes were analyzed with X-ray diffraction (XRD) and scanning electron microscope (SEM). The results indicated that Gd3Ga5O12 (GGG) nanometer powders with sphere shape and homogeneous dispersion were obtained when the samples were fired at 1000 ℃ for 12 h. The size of precursor particles increased with increasing of the sintering temperature. The strongest fluorescence emission peak appeared at 1062.7 nm which corresponds to Nd3+(4F3/2→4I11/2) transition.