Yttrium aluminum garnet (YAG) transparent ceramic has been proved to be one of the best solid-state laser materials in the history of quantum electronics. Its indisputable dominance in solid-state laser application is determined by its unrivalled optical, mechanical and thermal properties. During the fabrication of YAG transparent ceramic, agglomeration of YAG nanopowders can deteriorate the performance of transparent ceramic. YAG nanopowders are prepared by co-precipitation, then deagglomerated by ball milling and adding Dolapix CE-64. YAG nanopowders and its slurry are characterized by X-ray diffraction (XRD), Zeta potential, laser granulometer and scanning electron microscope (SEM). The results show that YAG nanopowders are well deagglomerated by adding 10 percent of Dolapix CE-64 and ball milling of 24 h.