Rattle-type Au@MnO2 hollow nanospheres (R-Au@MnO2) were successfully synthesized through a redox reaction between KMnO4 and Au-cored carbon spheres (ACCSs) which were fabricated by hydrothermal method using aqueous solution of HAuCl4 and glucose. The phase of the MnO2 shell was determined by X-ray diffraction as delta-MnO2. R-Au@MnO2 hollow nanospheres exhibited enhanced catalytic activity that CO could be converted to CO2 by 90% at 103 degrees C, and also showed good catalytic stability.