Abstract: For the difficult-to-capture micron and nanometer particulate matter in diesel engine exhaust， especially particles with diameters smaller than 0.05 μm， a three-stage tandem purification system， consisting of a corona charging-agulation device， a diesel particulate filter（DPF） and a plate-type dust collector， was constructed. Through the self-designed wire-cylinder charging and agglutination unit， the micron and nanometer particulate matter was charged and collided to agglomerate and increase in size， thereby enhancing the subsequent capture efficiency of the DPF. The fine particulate matter（PM） that escapes was then subjected to a secondary electric field capture by the rear plate-type dust collector. The system achieved a collaborative purification efficiency of 94.15% for PM， significantly higher than that of traditional DPFs.