A series of Eu-doped Ba2MgSi2O7 phosphors are prepared in air atmosphere by the high temperature solid-state reactions. A reduction of Eu3+ to Eu2+ ion is validated in Ba2MgSi2O7 via emission and excitation spectra measurement. The results show that the photoluminescence (PL) intensity of the Ba2MgSi2O7Eu2+ prepared in air at 1350 ℃ with quench cooling was enhanced about 6 times compared with that of Ba2MgSi2O7Eu2+ prepared in air at 1250 ℃ with furnace cooling. Moreover, the PL intensity of the Ba2MgSi2O7Eu2+ is increased by adding NH4F flux. The PL intensity of Ba2MgSi2O7Eu2+ phosphor containing 4% NH4F (molar fraction) is 5 times as high as that of the Ba2MgSi2O7Eu2+ phosphor without NH4F.