In order to improve the luminescent character of Y2O2S∶Eu3+, the method of improving crystallinity of primary raw material Y2O3 is used. The emission intensity of red phosphors Y2O2S∶Eu3+ is effectively enhanced 5％ and 10％ respectively at the voltages of 20 kV and 25 kV while the other primary properties of application in chromaticity, granularity and decentralization are not changed. The voltage resistance character (relation between emission intensity and excitation voltage) is elevated. The origins of the emission intensity enhancement and excitation voltage elevation are discussed and analyzed preliminarily. It is likely that the abnormal change and defect of crystal lattice led by the substitution of larger radius Eu3+ ion for smaller radius Y3+ ion are reduced by the better crystal quality of Y2O2S∶Eu3+ from the better crystallinity of raw material Y2O3. Because the crystal field condition of Eu3+ ion is improved, radiationless process and energy loss led by crystal defect are cut down, the emission efficiency of Y2O2S∶Eu3+ phosphors is enhanced and its voltage character is improved. The experiment shows that the decomposing temperature to get the high crystallinity Y2O3 is about 1400 ℃.