Bi2O3 nanomaterials doped with Eu3+ and Nd3+ ions have been synthesized by a simple hydrothermal process at 180oC for 48 h. Bi(NO3)3.5H2O and KOH were used as raw materials. The as-prepared materials were characterized by X-ray diffraction (XRD). The data showed that the doped Bi2O3 materials were crystalized in a monoclinic crystal structure with space group of P21/c and cell parameters of a=5.8499 ?, b=8.1698 ? and c=7.5123 ?. The morphology of the obtained nanomaterials was investigated by field emission scanning electron microscope (FESEM). The morphology was remained unchanged after doping the rare elements into Bi2O3. However, different morphology of the compounds was achieved. The FESEM images showed that the materials were composed of micro-nano rods, nanoparticles and flower structures. Elemental analyses of the doped nanomaterials were performed by energy-dispersive X-ray spectrometry (EDS). Also cell parameter refinements and interplanar spacing (d) of the obtained materials were investigated.