The surface modification reaction was applied to the spherical nanoparticles of an elasticoluminescent material, europium-doped strontium aluminate, to improve the water-resistant property. The superior resistibility of the resulting material against water treatment was proved by scanning electron microscopy, photoluminescence, X-ray diffraction, and Fourier transform infrared measurements. Structure and property of the coating layer was also studied by solid state P-31 magic angle spinning nuclear magnetron resonance, atomic emission spectrometry, and zeta potential measurements. (c) 2007 The Electrochemical Society. All rights reserved.