In this paper, effect of Eu 3+ doping concentrations on microstructure and photoluminescence of Sr 2 SiO 4 phosphors was investigated. The Sr 2−x SiO 4 :xEu 3+ phosphors with x=0.05, 0.1, 0.2, 0.3 were synthesized by microwave assisted sintering at 1200°C for 60min in air. X-ray powder diffraction analysis confirmed the formation of pure Sr 2 SiO 4 phase without second phase or phases of starting materials irrespective of the adding amount of Eu 3+ . From scanning electron microscopy image, it is found that with more Eu 3+ ions introduced to Sr 2 SiO 4 , the shape of the particles is not much different from each other, but the particle size decreases significantly from 1 to 2μm (when x=0.05) to less than 500nm (when x=0.3). The emission spectrum was located obviously at 617nm as the excitation spectrum at λ ex =395nm, and it had best emission intensity when x=0.1.