The PMA/Eu2O3 porous and layered nanocomposite was prepared by in situ polymerization and characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), and infrared ray (IR). Microscopic investigation of the nanocomposite was carried out by atomic force microscopy (AFM). The results showed that the shape of the composite was layered and porous. Eu2O3 was grafted when methyl acrylate (MA) polymerized; thus Eu2O3 particles appeared on both sides of the chains of polymeric methyl acrylate (PMA).