YAG:Ce3+ phosphor powders were synthesized using a Al_2O_3 seed (average particle size: 5 µm) by the polymer solution route. PVA solution was added to the sol precursors consisting of the seed powder and metal nitrate salts for homogeneous mixing in atomic scale. All dried precursor gels were calcined at 500°C and then heated at 1400°Csim1500°C in N_2/H_2 atmosphere. The final powders were characterized by using XRD, SEM, PSA, PL and PKG test. All synthesized powders were crystallized to YAG phase without intermediate phases of YAM or YAP. The phosphor properties and morphologies of the synthesized powders were strongly dependent on the PVA content. Finally, the synthesized YAG:Ce3+ phosphor powder heated at 1500°C, which is prepared from 12:1 PVA content and has an average particle size of 15 µm, showed similar phosphor properties to a commercial phosphor powder.