A white-emitting long-lasting phosphor is synthesized by the conventional high temperature solid-state method. After irradiation by 185 or 210 nm UV light for 1 min, the Dy3+-doped Sr2SiO4 phosphor emits white color long-lasting phosphorescence, and the phosphorescence can be seen with the naked eye in the dark clearly for more than 1 h even after the irradiation source has been removed. XRD, PL, and TL spectra are used to characterize this phosphor. It is considered that the long-lasting phosphorescence is due to persistent energy transfer from the e-traps to the Dy3+ ions to create the white-emitting long-lasting phosphorescence.