A simple and efficient route to prepare inorganic compound/polymer composites in CO2-based supercritical solution is presented. By this method, using polymeric hollow spheres as a substrate and Eu(NO3)(3) as precursor, Eu2O3/polymer composites are successfully fabricated via the decomposition of the precursor in a supercritical CO2/ ethanol mixture at 120 degrees C. The resulting composites are characterized by means of transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. It is indicated that besides being decorated on the outer surface of the polymer spheres, Eu2O3 nanoparticles are imbedded in the shell and further into the hollow cavity of the polymer spheres. The loading content and particle size of Eu2O3 on the polymer spheres can be controlled by changing the concentration of precursor in the solutions. The photoluminescence spectrum of the composites exhibit two peaks at 592 and 615 nm, which indicates that the composites can be used as optical material to emit red light. This method is also extended to the preparation of other inorganic compound/ polymer composites with different functions.