The catalytic activity of BaAl2O4 In the simultaneous removal of soot and NO,, was evaluated by Temperature Programmed Reaction (TPR). It was found that BaAl2O4 could effectively catalyze the reaction of soot with NOx under various reaction conditions. Compared with non-catalytic combustion, ignition temperature, T-ig, and maximum combustion temperature, T-m, of soot decreased by more than 175 degrees C and 240 degrees C, respectively. Tight contact of soot with BaAl2O4, higher O-2 content and a lower flow rate of synthesized gases were beneficial to the catalytic reaction. It was confirmed by Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) analysis, that the reaction of soot with NO2(ad) was the most important factor in simultaneous removal of soot and NOx, in which NO2(ad) existed on BaAl2O4 in the form of monodentate nitrate, bridged nitrate and ionic nitrate.