Abstract: In order to further enhance the separating performance of the FGX-9 dry cleaning machine,industrial test is made with the machine for treating the raw coal from Fuxin Coal Mine,so as to determine the effect on separation performance of the machine produced by common internal factors,such as vibration amplitude,frequency,inclination angle of deck,air pressure and volume,and to define the optimum technical parameters.Test result shows that under the test condition: the yield of clean coal drops with the increase of vibration amplitude,and at an amplitude of 8mm,a best separating result can be expected; the yield of clean coal decreases with the increase of vibration frequency（The machine generally operates with a vibration frequency of 35~50 Hz）,and the ash of clean coal tends to first decrease and then go up; in industrial operation of the machine,the quality of clean coal can be improved through appropriately increasing vibration frequency; at a vertical inclination angle of 0°,the yield of clean coal increases gradually with accordingly a higher ash with the increase of horizontal inclination angle; at a horizontal inclination angle of 7°~8°,a best quality of clean coal can be obtained; with the increase of air volume,both clean coal yield and ash first drop and then increase,and at an air volume of 70,000~80,000 m³/ h,the machine can work with the best separating performance.The study made in the paper is of important guiding significance for the enhancement of the separating performance of the FGX-9 dry cleaning machine.