Rare earth long afterglow phosphors Sr2MgSi2O7:Eu2+,Dy3+ was synthesized by a modified solid-state reaction using H3BO3 as auxiliary reagents. In order to promote the emission properties of Sr2MgSi2O7:Eu2+,Dy3+, samples of Sr2MgSi2O7:Eu2+,Dy3+ were prepared and the effect of manufacturing elements including the concentration of H3BO3 and environmental factor of calcining temperature, concentration of Eu2+ and Dy3+ ions, external environmental factors of applications such as fiber-forming polymer as well as the addition of Ca2+ ion on its emission property were investigated through evaluating their emission spectra. The results showed that the molar ratio of the Eu2+ ions and Dy3+ ions, the amount of doping H3BO3, calcining temperature and fiber-forming polymer had little effect on the position of the emission peak and the shape in the luminescence, but greatly influenced the emission intensity of luminescent materials. The effect of Ca2+ ion doping was further studied. Ca2+ influenced not only the intensity but also the wavelength of emission and spectra of the emission peak shifted to longer wavelength as the concentration of Ca2+ increased.