Abstract: Sphere-like and rod-like Eu₂O₃ and Sm₂O₃ polycrystalline nanoparticles were fabricated by using a surfactant-and ultrasonic-assisted precipitation strategy.The physical properties of these nanomaterials were characterized by means of transmission electron microscopic(TEM),selected area electron diffraction(SAED),X-ray diffraction(XRD),nitrogen adsorption-desorption,and ultravioletvisible diffuse reflection spectroscopic(UV-Vis DRS) techniques.It is shown that the sphere-like body-centered cubic Eu₂O₃ and monoclinic Sm₂O₃ nanoparticles obtained with sodium dodecylsulfate as surfactant and the rod-like orthorhombic Eu₂O₃ and body-centered cubic Sm₂O₃ nanoparticles fabricated with polyvinylpyrrolidone as surfactant possessed a BET surface area of 44~49 and 34~37m²/g,respectively.In addition to a stronger absorption of UV light(λ<390nm),the sphere-like and rod-like Eu₂O₃ and Sm₂O₃ samples exhibited different absorption of visible light(390nm<λ<535nm).Such a difference in light absorption behavior might be a result due to various surface morphologies and crystal structures of the so-obtained rare earth oxides.