An attempt has been made to explore how the luminescence properties change when rare-earth elements are substituted for different cations in the host. We synthesized Eu2+-doped Ba3Ce(PO4)(3) via a high-temperature solid-state reaction process, substituting for Ba2+ and Ce3+ ions and naming them Ba3Ce(1-x)(PO4)(3):xEu(2+) and Ba(3-y)Ce(PO4)(3):yEu(2+), respectively. The structure, X-ray diffraction with Rietveld refinements, reflectance spectra, and luminescence characterization of the phosphor are measured to explore the difference of substituting for different ions. In order to explain why all of the emission peaks containing the highest peak and the fitting values of Ba3Ce(1-x)(PO4)(3):xEu(2+) are shorter than those of Ba(3-y)Ce(PO4)(3):yEu(2+) (when x = y), we built a model by N, which represents the surrounding environment. This mechanism is predicted to be general to Eulytite-type orthophosphates and will be useful in tuning optical and other properties whose structural disorder influences the crystallization and is sensitive to local coordination environments. Substituting different cations in tuning of the red shift, widening of the full width at half-maxima (fwhm), and thermal quenching were also observed.