Single-phase KLaSr3(PO4)(3)F: Sm3+ phosphors with fluorapatite structure were prepared via high-temperature solid-state method in air atmosphere for the first time. The X-ray diffraction, scanning electron microscope, diffuse reflectance spectra, photoluminescence spectra, and temperature-dependent emission spectra, as well as lifetimes were measured to characterize the as-prepared phosphors. Phase results indicated that KLaSr3(PO4)(3)F: Sm3+ belongs to hexagonal system with a space group of P-6. Photoluminescence measurements showed the emission spectrum was composed of four sharp peaks at about 564, 602 (the strongest one), 646, and 702 nm, corresponding to the (4)G(5/2)-H-6(J) (J=5/2, 7/2, 9/2, and 11/2) transitions of Sm3+ ions. The optimum doping concentration of Sm3+ ions was turned out to be 0.03 (mol), and the mechanism of energy transfer among Sm3+ ions was considered to be dipole-dipole interaction by using Dexter's theory. In addition, the critical distance R-c for energy transfer among Sm3+ ions were calculated to be 9.97 angstrom according to Blasse concentration quenching method. The selected KLa0.97Sr(PO4)(3)F: 0.03Sm(3+) exhibited high thermal stability with an activation energy of 0.163 eV. Besides, the Commission International de l'Eclairage chromaticity coordinate of the phosphor were located in the orange-reddish light region.