Rare earth activated oxides phosphors have attracted much attention in the field of solid state lighting (SSL) due to their irreplaceable advantages. In this work, a series of CdMoO4:aSm3+ and CdMoO4:aSm3+, M+ (M = Li, Na, K) phosphors were prepared by high temperature solid-state reaction. X-ray diffraction and photoluminescence spectroscopy were utilized to characterize samples properties. The concentration dependent luminescence of Sm3+ activated CdMoO4 sample was investigated in detail. The optimum doping concentration of CdMoO4:aSm3+ was 0.015 (1.5 mol%) and the corresponding concentration quenching mechanism was verified to be the electric dipole–dipole interaction. Also, CdMoO4:0.015Sm3+ phosphor exhibits bright red–orange emission with excellent CIE coordinates (x = 0.5887, y = 0.3908) under the excitation at 346 nm. In addition, it was observed that the luminescence intensity of Sm3+ and Na+ co-doped sample was 3.667 times stronger than that of the Sm3+ single doped sample under the same excitation wavelength. Meanwhile, when Na+ was incorporated into the CdMoO4 matrix, the color purity of CdMoO4:Sm3+ phosphor was enhanced from 78.0 to 81.3 %. These red–orange phosphors are promising for application in white light emitting diodes.