Nanocrystals of CeO2 with different doping concentrations of Sm3+were synthesized by a novel and costeffective method. The crystal structure, morphology and particle size were systematically investigated by X-ray diffraction,scanning electron microscopy and transmission electron microscopy. Effects of the annealing temperature and doping concentrations on the microstructural properties of the crystals were studied. X-ray diffraction analysis indicates that the cubic structure of the Ce O2 is not affected by the doping of Sm3+up to a doping concentration of 20%. Different structural parameters such as lattice constant, surface area, bulk density and porosity of the crystal were determined and discussed.Microscopic images of the CeO2:Sm3+suggest that the thermal decomposition of oxalate precursor is a suitable synthesis pathway to produce uniform-sized microparticles and nanoparticles. The influences of annealing temperature and doping concentration of Sm3+on the optical properties of the nanocrystals were also discussed. The photoluminescence excitation spectra reveal that the charge transfer band is redshifted with increasing annealing temperatures. Emission attains its maximum intensity for Sm3+concentration of 1%, and higher concentrations lead to emission quenching. Nanocrystals of CeO2 with different doping concentrations of Sm3 + were synthesized by a novel and costeffective method. The crystal structure, morphology and particle size were systematically investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Effects of the annealing temperature and doping concentrations on the microstructural properties of the crystals were studied. X-ray diffraction analysis indicates that the cubic structure of the Ce O2 is not affected by the doping of Sm3 + up to a doping concentration of 20%. constant, surface area, bulk density and porosity of the crystal were determined and discussed. Microscopic images of the CeO2: Sm3 + suggest that the thermal decomposition of oxalate precursor is a suitable synthesis pathway to produce uniform-sized microparticles and nanoparticles. The influences of annealing temperature and doping concentration of Sm3 + on the optical properties of th The photoluminescence excitation spectra reveal that the charge transfer band is redshifted with increasing annealing temperatures. Emission attains its maximum intensity for Sm3 + concentration of 1%, and higher concentrations lead to emission quenching.