The blue-emitting CaAl 2B 2O 7:Eu 2+ phosphor was prepared at 800 °C by a modified solid-state reaction. The results of X-ray powder diffraction (XRD) analysis confirmed the formation of CaAl 2B 2O 7:Eu 2+. Photoluminescence (PL) spectroscopy showed that the phosphor could be excited efficiently by UV-vis light from 250 to 410 nm, and exhibit blue emission (460 nm). The emission intensity of CaAl 2B 2O 7:Eu 2+ phosphor varies with the increase of Eu 2+concentration. The mechanism of resonance-type energy transfer from Eu 2+ to Eu 2+ was established to be electric multipole-multipole interaction. TEM images showed that the grain size of CaAl 2B 2O 7:Eu 2+ is about 45 nm, which is in full agreement with the theoretical calculation data from the XRD patterns.