In this experiment, BaMgAl10O17:Eu2+ (BAM) phosphors were coated with thin SiO2 film by using a radio frequency (RF) sputtering method and investigated their electro-optical properties. It was revealed that the phothluminance properties of BAM phosphors coated with 2 not SiO2 film were improved, when compared with non-coated ones and more thickly coated ones. The improvement may be due to the increase of an effective excitation transmitted into the BAM phosphors and the increased vacuum ultraviolet (VUV) absorption of the phosphors via SiO2. And the decrease in luminance seen in the thickly coated phosphors may be due to the interruption of the thick SiO2 film in the penetration of VUV. From the results of the experiment, we find that a proper coating of BAM phosphors with thin SiO2 film is a good way for improving the luminance.