The Sm2+-doped SrZn2(PO4)(2) phosphor was prepared by the high temperature solid-state reaction method. The temperature-dependent emission spectra and luminescence decay of Sm2+ ions were investigated from 10 to 300 K. The investigation was focused on the site distributions of Sm2+, ions in this host, which exhibited different spectroscopic features at varying temperatures. Two crystallography sites existed for Sm2+ ions in this host below 170 K, where no energy transfer could be detected between them. However, only one Sm2+ site was left from 170 K to room temperature. The photostability of the Sm2+ ion was evaluated by the photobleaching method. This investigation would be helpful for understanding the doping mechanism and applications of rare-earth ions doped in this phosphate host. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3190479] All rights reserved.