Using non-thermal plasma devices and reactor based on dielectric barrier discharge principles, simulation experiment and bench test were carried out. Experimental result indicated that non-thermal plasma produced by dielectric barrier discharge could decompose particulate matter in diesel exhaust effectively, and correlative chemical reaction mainly took place in the channels of micro discharge, decomposition rate of particulate matter increased with the energy density. The non-thermal plasma reactor could transform NO in the exhaust to NO2, but could not reduce the total amount of nitric oxides. Decomposition and conversion rate of HC and NO in diesel exhaust when treated with non-thermal plasma descend along with the quantity of particulate matter in the exhaust. 