Nitrogen monoxide(NO) emitted from automobile exhaust and other industrial sources contributes largely to a variety of environmental problems, such as the formation of acid rain and photochemical smog Therefore, the catalytic reduction of NO has become one of the urgent environmental issues In the present study, a series of Au/Mn 2O 3/Al 2O 3 catalysts, with different Mn 2O 3 loadings, were prepared by deposition precipitation The crystallite size of Au before and after reaction was characterized by XRD The activity of catalysts in the selective catalytic reduction of NO using propane in the presence of oxygen was evaluated It is found that the catalytic activity of Au/Mn 2O 3/Al 2O 3 is higher than that of Au/Al 2O 3 and Cu ZSM 5 at feed gas(0 6%NO+1 2%C 3H 8+5%O 2+He) and GHSV 5?000?h