Long lasting alkaline earth silicates, Ca 2 MgSi 2 O 7 :Eu,Dy,Nd was prepared under a reduction atmosphere through solid state reaction. The obtained phosphor was characterized by means of X-ray diffraction (XRD) and photoluminescence spectrum (PLS). The crystal structure of Ca 2 MgSi 2 O 7 :Eu,Dy,Nd phosphor was refined by Rietveld analysis. The obtained Ca 2 MgSi 2 O 7 :Eu,Dy,Nd phosphor showed a yellow-green emission peaking at 518 nm, which is ascribed to the luminescent emission of the Eu 2 + that occupied the octa-coordinated Ca 2 + sites in the Ca 2 MgSi 2 O 7 host. The electron affinity (ea) value for Eu 2 + in [EuO 8 ] was calculated to 1.9 eV. The decay profile and the emission spectrum indicated that when the value of Dy/Eu is increasing, there is a concentration quenching of Eu 2 + .