An active perovskite-type catalyst (La0.8K0.2Cu0.05Mn0.95O3) was prepared and characterized using XRD, BET, and SEM. Then, the effect of catalysis on plasma assisted catalytic removal of nitrogen oxides and soot was investigated by combining temperature programmed reaction (TPR) and the analysis of Fourier transform infrared spectroscopy (FT-IR). When the C3H6 concentration in the feed gas is 0.27%, the maximum NOx removal rate increases from 43.5% to 72.2% after adding catalyst. FT-IR results indicate that the addition of catalyst will promote the removal of NOx, HC, and soot. There is still great amount of NOx and HC remaining after plasma reaction, little NOx and almost no HC after catalytic reaction, and no NOx and HC after plasma assisted catalytic reaction.