Abstract: A non-thermal plasma (NTP) reactor was designed based on corona discharge to reduce the particulate matter (PM) emitted from a diesel engine. Raw PM, PM escaped from NTP reactor, and PM aggregation sampled at 100% engine load were used to perform the thermo-gravimetric (TGA) experiments after being volatilized the VOC contained in PM. The activation energy was calculated based on the results of TGA experiments. The results show that the profiles of PM pre-treatment present double peaks phenomenon. The peak point of pre-treatment profiles of PM escaped from NTP reactor moves to higher temperature compared to raw PM. The oxidation temperature of PM aggregation is higher than raw PM while it is lower for PM escaped from NTP reactor. The calculated activation energy of PM escaped from NTP reactor is the highest among the samples.The activation energy calculated using KAS method is lower than that using single-ramp rate method and the difference is enlarged when increasing the ramp rate of single-ramp rate method.