Effects of ionic liquid-assisted on electrolyzed desulfuration of coal water slurry (CWS) in HCl system were investigated by constant-current electrolysis. The results indicated that the desulfuration effects from CWS electrolysis in the HCl system were improved, and the removal effects of organic sulfur in coal were improved as ionic liquids increased. On the other hand, reduction of electrolysis on cathode showed that hydro-desulfuration ratio with 1-butyl-3-methylimidazolium bromide (C8H15N2Br) was higher than that with 1-butyl-3-methylimidazolium chloride (C8H15N2Cl), and hydro-desulfuration ratio with pyridine ring ionic liquids was higher than that with imidazole ring. The results of ash composition showed Fe-containing mineral matters were removed by electrolysis on anode. However, they were not removed by electrolysis on cathode. In addition, the desulfuration ratio of CWS electrolysis without membrane was between anode and cathode electrolysis ratio. Finally, the mechanism of ionic liquid-assisted on electrolyzed desulfuration of CWS in HCl system was proposed. Crown Copyright (c) 2012 Published by Elsevier B.V. All rights reserved.