The thermo-gravimetric properties of PM treated by non-thermal electro-discharge were studied by the experimental method. A non-thermal electro-discharge reactor was designed to trap PM based on the electrostatic theory, and a test rig for comparison and analysis was built. The content of soluble organic and solid carbon particles in PM was compared and analyzed by thermo gravimetric technology. The test and the analysis result concluded that non-thermal electro-discharge reaction can make soluble organic fraction produce incompleteness chemistry reaction. Voltage change of non-thermal electro-discharge is the key factor to affect the PM composition. Collection efficiency of PM for non-thermal electro-discharge reactor increased and the content of soluble organic fraction in PM decreased along with the voltage increase of non-thermal electro-discharge.