Phosphor coated with wide bandgap metal oxide which can be used for a plasma display panel (PDP) has a surface that is coated with a continuous, thin film of wide bandgap metal oxide. In preparing the phosphor coated with wide bandgap metal oxide, a pH of the wide bandgap metal oxide precursor solution containing an organic solvent and water is adjusted to 0.1 10 and heated under a reflux, thereby obtaining a metal hydroxide gel. The wide bandgap metal hydroxide gel is made to contact a phosphor for a PDP, thereby obtaining the gel-coated phosphor. The gel-coated phosphor is then dried and sintered.