Abstract Maleic anhydride was modified by long chain 1-octadecanol to mono-octadecyl cis-butene dicarboxylate (MAO), which has both hydrophilic and lipophilic groups. Then, a novel sort of corresponding amphiphilc rare earth (Gd 3+, Y 3+, Eu 3+) complex with the as-derived MAO was synthesized. Then, nanosized Gd x Y 2− x O 3:Eu 3+ ( x = 0.2, 0.6, 1.0, 1.4, 1.8) was achieved using this novel amphiphilic rare earth complex as precursor molecule which can form nanosized micelle-like aggregates by special self-assembly. Scanning electronic microscope (SEM), transmission electron microscopic (TEM) and X-ray diffraction (XRD) were used to characterize the morphology and particle size of this nanometer material, which present the regular nanocrystal with particle size of 70 nm. Besides that, this nanometric material exhibits an especially strong emission at 610 nm.