Calcium magnesium chlorosilicate doped by europium, Ca8Mg(SiO4)4Cl2:Eu2+, was prepared by the solid state reaction at high temperature. The compound obtained is pure Ca8Mg(SiO4)4Cl2 phase with cubic structure. Its average particle size is 5 μm, and it has good dispersity and morphological form. The excitation spectrum of Ca8Mg(SiO4)4Cl2:Eu2+ is a wide band, which covers from 270 to 480 nm. The emission spectrum is also a wide band peaked at 510 nm. The luminescent intensity reaches to the maximum when the concentration of Eu2+ is 2%. The wavelength of emission and excitation of the phosphor with various Eu2+ contents keeps constant. This spectrum range matches violet and blue LED chips very well, and its strong luminescence intensity is suitable for a green phosphor of tricolor phosphor of white light LED.