To study the effect of removing sulfur from coal by microwave-assisted H₂O₂ compound system, coal samples from Yuanyang Lake in Ningdong, Ningxia were selected as the research object. The coal samples were treated with citric acid, sodium hydroxide and hydrogen peroxide, respectively. The microwave irradiation power was 900 W, and the irradiation time was 5 min. The results show that the desulfurization rate treated by hydrogen peroxide alone is 34.29%. The maximum desulphurization rates for two compound systems of the hydrogen peroxide with citric acid, and hydrogen peroxide with sodium hydroxide compound system are as high as 43.67% and 45.31% respectively. During the desulfurization process, most pyrite sulfur is removed. Sulfur forms in coal are changed into high state gradually, and in particular, thiophene is partially changed into sulfoxide, sulfone and sulfate sulfur. Microwave assisted compound agent treatment can be used to increase the contact area between the coal sample and the compound agent. The possibility of contact between hydroxyl radical and sulphur-containing groups in the coal is increased, so as to improve the desulfurization rate.