The Eu2+-doped NaBaPO4 phosphor was prepared by high-temperature solid-state reaction. The photoluminescence excitation and emission spectra and the luminescence quantum efficiency of Eu2+ ions were investigated. The dependence of luminescence intensity on temperatures and the temperature-dependent decay times of Eu2+ ions doped in NaBaPO4 were measured and discussed. The natures of the Eu2+ emission in NaBaPO4, e. g., the Stokes shift, the luminescence quenching temperature (T-0.5), the activation energy for thermal quenching (delta E) were reported. In addition, the crystal structure and the site occupancy of Eu2+ ions doped in NaBaPO4 crystal lattice were discussed. Two different Eu2+ centers were assigned according to the crystal structure and the luminescence characteristics of Eu2+ ions. The phosphor shows an excellent thermal stability on temperature quenching effects. With the increasing of temperature, the emission bands show the abnormal blue-shift.