Non-thermal plasma (NTP) technology was applied to promote the temperature-programmed oxidation (TPO) of soot over a perovskites type of La0.8K0.2MnO3 catalyst. The O radicals originating from the decomposition of O-2, as well as NO dissociation if nitrogen oxide were involved, reduce the ignition temperatures of soot. In NO-O-2-He, for example, the ignition temperature decreased to 240 degrees C from 290 degrees C as the voltage increased from 0 kV to 15 W The higher voltage also benefited the adsorption of NO molecules onto the catalyst surface (NOad). As a result, the maximum N-2/NO ratio (conversion ratio of NO into N-2) rose from 23 % to 53 %. Some of the NO molecules were dissociated into N and O radicals in plasma, and hence, the N-2/NO ratio was further enhanced due to the combination of N atoms. In any case, the redox process between NOx and soot proved to be important in soot oxidation.