To understand roles of inherent mineral matters in lignite water slurry (LWS) electrolysis, lignite and demineralized lignite electrolyses were carried out in H2SO4 system. The results showed that cell voltage for LWS electrolysis was lower than that for demineralized lignite water slurry (DLWS) under constant current condition. Some inherent mineral matters changed into the corresponding metal ions which entered into electrolyte, and thus improved the electrolysis oxidation reactions for coal organic structure. Meanwhile, the relative amount of O-containing functional groups in demineralized lignite increased with electrolysis time, improving its pyrolysis reactivity. However, the pyrolysis reactivity of raw lignite decreased due to the removal of the inherent mineral matters from electrolysis. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.