CO Oxidation / Rutile SnO 2 / Praseodymia / Sn-Pr Binary Catalysts / Pr 2 Sn 2 O 7Praseodymia-doped SnO 2 catalysts were prepared with precipitation-deposition method and used for CO oxidation. The samples were characterized by means of Inductive Coupled Plasma Emission Spectrometery (ICP), N 2 Adsortion-desorption with Brunauer-Emmett-Teller Technique (N 2 -BET), X-ray Podwer Diffraction (XRD), H 2 Temperature Programmed Reduction (H 2 -TPR), Thermal Gravity Analysis-Differential Scanning Carorimetry (TGA-DSC) and X-ray Photoelectron Spectroscopy Analysis (XPS). Praseodymia was found to disperse finely onto the surface of rutile SnO 2 , and had some strong interaction with it, thus stabilizing the surface area of the resulted catalysts as well as producing larger amount of active oxygen species. As a consequence, the CO oxidation activity of the Sn-Pr composite metal oxide catalysts was significantly enhanced. The activity of the catalysts also improves with the increasing of praseodymia addition amount, mainly due to the formation of more active oxygen species and increased surface areas.