Abstract: In order to reduce the sulfur and ash content of jigging coarse clean coal in Lucun coal preparation plant,based on the best flotation and magnetic separation test condition,use the flotation,grinding-flotation,grinding-magnetic separation,flotation after magnetic separation,magnetic separation after flotation and two section of magnetic separation processes analyzed sulfur and ash reduction effect of coarse coal,to determine the best separation process. Test results showed that after size fraction of coal sample crushed to ＜ 0. 5 mm,under the condition of slurry concentration is 110 g/L,inhibitor dosage is 1. 75 kg/t,collector dosage is 600 g/t,foaming agent is 68 g/t and flotation time is 2 min,the desulfurization and ash reduction effect is better. When the flotation clean coal yield is 88. 48%,the ash content is 3. 02%,the sulfur content is 1. 78%,ash reduction rate is 48. 40%,sulfur reduction rate is31. 26%,and the iron sulfide removal rate is 54. 89%.