The Ca2-xMgSi2O7∶xEu2+ green phosphor is synthesized by chemical coprecipitation. X-ray diffraction and the fluorescence spectrophotometry are used to investigate the structural and the luminescent properties of the Ca2-xMgSi2O7∶xEu2+ green phosphor. The result shows that the excitation spectrum of the Ca2-xMgSi2O7∶xEu2+green phosphor extends from 300 nm to 480 nm, and the peaks appear around 389 and 430 nm, thus the phosphor can be excited effectively by InGaN chip in a range of 360480 nm. The peak of the emission spectrum appears around 531 nm. The emission spectrum intensity first increases and then decreases with Eu2+ doping concentration increasing. The strongest emission intensity is obtained when Eu2+doping concentration reaches 0.04. The concentration self-quenching is attributed to the d-d interaction according to the Dexter theory.