Abstract: In allusion to the desulfuration characteristic of coal ash, the desulfuration of the ash and CaO, Al2O3 added to Changguang coal with different proportions at high temperature was studied.Sulphoaluminate as the main desulfuration product was analyzed by Xray diffraction and SEM visualization.Experimental results indicate that higher proportion of ash added can improve the desulfuration efficiency.The sulphoaluminate content in residue increases with increasing the addition of ash. The desulfuration efficiency of the additive CaO and Al2O3 is up to 24% at 1300℃, at the same time the sulphoaluminate is detected in the residue.