Pr-doped ZnO phosphor powders were prepared by dry reaction within evacuated sealed silica glass tube. Pr2O3 and Pr6O11 were used as additives. Pr concentrations were 0.5, 1, 3, and 5 mol%, and the sintering temperatures were 600, 800, and 1000 °C, respectively. Photoluminescence (PL) and PL excitation (PLE) spectra were measured to study luminescent properties of samples. Some samples showed the enhancement of green emission. This emission is related to native defects in ZnO. Based on the results of PL and PLE, the origin of the enhancement was discussed in view of native defects in ZnO and the defect-related complex in ZnO varistor ceramics. The possible origin is the increase of native defects such as VZn, OZn, and the complex in the vicinity of grain boundaries and ZnO matrix near the surface of grains. The increase of native defects and the complex are probably due to the existence of the Pr3+-ions with binding to native defects, which form the complex by Coulombic potential.