Abstract: With NaOH solution as assistant agent,coal desulfurizaition test was carried out to find out the influences of such factors as coal particle size,concentration of NaOH solution,irradiation time,and power on desulfurization,and the changes of minerals and sulfur-containing functional groups in coal before and after desulfurization were also studied.It was indicated that,in the selected range of parameters,decreasing the coal particle size would contribute to desulfurization,and increasing the NaOH solution,irradiation time,and power would result in a better desulphurization efficiency.According to the analysis of XRD and FTIR of coal samples before and after desulfurization,the content of minerals decreased significantly without any striking defferences in species,and the absorption peaks of sulfur containing functional groups decreased without any significant damage to the coal structure.