Europium doped yttrium oxide (Y2O3:Eu) has been one of the most effective phosphors for red light. To enhance the efficiency of Y2O3:Eu further more, many researchers have tried to synthesize round type, non-porous Y2O3:Eu particles with uniform size. Flame pyrolysis and solution phase colloidal synthesis have been the major methods to synthesize energy-efficient nanosize Y2O3:Eu phosphors. In this presentation, we developed a new method to synthesize energy-efficient Y2O3:Eu by combination of Y2O3:Eu with silica. Y2O3:Eu nanoparticle-silica composite materials was synthesized by the impregnation of yttrium and europium precursors inside the pores of mesoporous silica. Thermal treatment at 823 K in oxygen atmosphere converted metal precursors into Y2O3:Eu particles. The measurement of high-resolution transmission electron microscopy and x-ray diffraction pattern confirmed that Y2O3:Eu nanoparticles were incorporated inside the pores of mesoporous silica. Photoluminescence study showed that the efficiency of Y2O3:Eu nanoparticle-silica composite for red light emitting was much higher than that of bulk Y2O3:Eu, which was synthesized with the same treatment method without mesoporous template.