The Eu2+ and Dy3+ ion co-doped Sr3Al2O6 phosphor powders with long afterglow were prepared with high temperature solid-state reaction. The phase and the spectra properties of the material were characterized by X-ray diffraction (XRD) and fluorescence spectrophotometer. It was found that the sample is composed of pure Sr3Al2O6 phase. Furthermore, the emission peak of 537 nm under 360 nm excitation and that of 590 nm excited by 468 nm-light were obtained, respectively, and it is more interesting that the emission peaks were at 537 and 590 nm under 394 nm excitation. The effects of different excitation wavelengths on the emission spectrum were explained reasonably by the effect of nephelauxetic effect and crystal field. It revealed that the two types of luminescence with different color were caused by the differences of the center of gravity of the 5d excited state energy level and the split range of 5d energy level.