Elevation of temperature and pressure was used as an effective way to reduce the electrochemical resistance and improve the liquid mass transfer during the coal electrolysis without membrane, thus enhancing the desulfurization and hydrogen production. Results indicated that the high temperature and pressure have effectively reduced the electrochemical resistance (R-ct) and solution resistance (R-s) for coal electrolysis. The oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) potentials for coal-water slurry electrolysis was obviously seen to increase with increasing temperature and pressure. What's more, the difference between the potential of OER and the equilibrium potential of OER (overpotential) also increased with the intensified condition, which was defined as the metastable zone width (MZW), indicating that HO center dot formation was improved by the high temperature and pressure. As expected, the elevation in temperature and pressure has successfully resulted in the decrease in cell voltage and the increase in coal desulfurization during the electrolysis. (C) 2018 Elsevier Ltd. All rights reserved.