Abstract: Abstract: Much attention has been paid to diesel engines, due to their lower operating cost, higher thermal efficiency and durability. However, diesel engine emits high quantities of particulate matter (PM), which poses a huge threat to human health and environmental protection. Non-thermal plasma (NTP) technology is a promising method to control diesel emission. NTP includes many types of active radicals, such as atoms, ions, electrons, and excited state molecules, which can react with other substances without additional energy. Carbon monoxide, hydrocarbon and PM in diesel engine exhaust gas could be oxidized and eliminated at the same time with NTP injected into it. PM is one of the most obstinate contaminants in exhaust gas, because the structure of PM is intricate, the carbon in PM is difficult to be oxidized and PM contains many kinds of organic matter. To investigate the effect of NTP on multifarious components in PM, a self-designed NTP reactor was used and NTP which was generated from oxygen was injected into exhaust gas. These tests were performed at different reaction temperatures which contained 80, 120 and 160 ℃. Both raw PM and those treated by NTP were collected by filter membranes and detected in thermogravimetric (TG) experiments. The atmosphere was controlled during TG experiments, in which PM was heated to 450 ℃ in nitrogen firstly, after cooled to 250 ℃, PM was heated to 700 ℃ in oxygen. In this way, the volatilization behavior of volatile fraction (VF) and oxidation behavior of elemental carbon (EC) were monitored respectively in detail. The effect of NTP was evaluated by the change of start or ending moment of mass loss, and the differences among the TG and DTG curves. The Arrhenius equation was also used to extract the apparent activation energies and pre-exponential factors to estimate the change occurring in EC. The results showed that the greatest purification occurred at the reaction temperature of 120 ℃, and 66.79% of PM was removed. The activity of the active radicals increases with the rise of reaction temperature, facilitating the oxidation of the PM, however, the active radicals in NTP are labile at high temperatures and easy to decompose, with the content decreased, weakening the oxidation of PM. After NTP injection, the mass fraction of VF decreased, and the range increased with the raise of reaction temperature, which indicated that VF is easier to react with NTP than EC. The start moment and ending moment of VF volatilization scarcely changed. The mass fraction of low volatile fraction (LVF) was increased, manifesting there are some distinctions in the reaction between different kinds of VF and NTP. As for EC, the ignition temperature and burn out temperature decreased by 30-40 ℃ after the reaction with NTP. The DTG curves became gentler, and the temperature corresponding to the first peak of DTG curves hardly changed with reaction temperature. The apparent activation energies of EC reduced from 175.97-210.49 to 94.13-109.13 kJ/mol after the reaction. The apparent activation energies were mainly influenced by nanostructure and oxygen functional groups. The nanostructure of PM became more regular and the oxygen content in EC increased after oxidized by NTP. Based on the TG results of EC and the change of apparent activation energies, a conclusion has been drawn that the effect of reaction temperature increasing on the rest of EC is incarnated mainly on the raising of the mass fraction of half oxidized EC.