Y2O3:Eu luminescent particles were synthesized by the reaction between aqueous yttrium nitrate/europium nitrate salts and ammonium hydroxide solution by bulk precipitation and in the reverse microemulsion composed of NP-5/NP-9, cyclohexane, and water. Compared with Y2O3:Eu luminescent particles formed by the bulk precipitation method, the particles prepared in microemulsion showed a narrower size distribution, spherical shape, smaller size (20-30 nm), higher crystallinity, and stronger photoluminescence. Also, Eu-dopcd Y2O3 particles were deposited on the glass plate coated with indium tin oxide through the electrophoretic method. With these glass plates, low-voltage cathodoluminescence (CL) was measured. The nanoparticles synthesized in reverse microemulsion showed a stronger CL intensity and less current saturation than particles formed by bull; precipitation. These CL properties of particles formed in microemulsion might be attributed to the smaller particle size, the larger luminescent surface area, and more well-developed crystalline structure of phosphor than those formed by bulk precipitation.