Abstract: In view of the serious excessive emission of tail gas from trackless rubber tyred vehicle in coal mines,which is difficult to meet the non-road national stage Ⅳ,a tail gas purification system composed of “Exhaust Gas Recirculation(EGR) + Diesel Oxidation Catalyst (DOC) + Catalyst Diesel Particulate Filter (CDPF) + explosion-proof water cooling structure” was designed. GT-Power simulation software was used to establish the catalyst simulation model, and the influence of exhaust parameters on the catalytic reaction of DOC was obtained. On this basis,the tail gas purification device was developed for the explosion- proof diesel engine of TDE6105DZLQFB02 non-road national stage Ⅲ, and the performance and emission charateristics of the diesel engine were compared. The test results show that after the tail gas purification device is installed,the purification efficiency of CO,HC,NO_x and PM of the test vehicle under each working condition reaches 96. 80%,50. 95%, 25. 50% and 95. 20% respectively,which can meet the limit of non-road national stage Ⅳ.