Abstract: A series of TiO₂ supported manganese oxide catalysts, MnO_x/TiO₂ , were prepared by wet-impregnation method for the low temperature selective catalytic reduction (SCR) of NO with ammonia. WO₃ with different loadings was added to MnO_x /TiO₂ samples to investigate its possible influence on the catalytic activity of MnO_x /TiO₂ by using several characterization techniques including BET surface area, laser Raman spectroscopy (LRS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction(XRD). The research shows that minute addition of 5% WO₃ raises the catalytic performance of MnO_x /TiO₂ catalyst effectively by expanding the carrier’s surface area, improving its thermal resistance, increasing surface Brnsted acids and NH₃ adsorption capacity, and broadening the temperature window of SCR reaction. The MnO_x -WO₃/TiO₂ shows better SCR activity than WO₃- MnO_x /TiO₂ in terms of impregnation sequence. The adsorption peaks of NH₃ on surface of catalysts will be weakened or lost with temperature increasing, and the denitration reactivity curve of catalysts shows a maximum with the increase of temperature.