Abstract: Blue-emitting long-lasting phosphors Sr_2Al_6O_(11)∶Eu~(2+),Dy~(3+) were synthesized by conventional solid state reaction method. The effects of sintering temperature on the phase-formation and the luminescent properties of the Eu~(2+)and Dy~(3+) co-doped blue strontium aluminates were investigated. Phase identification was carried out by X-ray powder diffraction analysis. Excitation and emission spectra were recorded using a luminescence spectrometer, and afterglow curves were measured by a photometer. The results revealed that with the calcining temperature rising from 1100 ℃ to 1300 ℃ gradually, the aluminate rich in strontium changed to the aluminate rich in aluminum while emission band shifted to the shorter wavelength side, and then to the longer wavelength side. The phosphor with a main phase Sr_2Al_6O_(11) and an emission peak at shortest wavelength of 468 nm was synthesized with a calcining temperature of 1200 ℃.The decay time (≥1 mcd/m2) of the phosphor whose main phase was Sr_2Al_6O_(11) reached 240 min.