The hybrid sulfur (HyS) thermochemical process is a promising approach for massive hydrogen production with nuclear or solar energy, while the SO2 depolarized electrolysis (SDE) is the crucial part of the HyS process. The influences of electrolysis conditions including temperature and electrolyte concentration, as well as the preparation conditions of the membrane electrode assembly (MEA), i.e. the resin content in catalyst layers, hot press temperature and catalyst loading, on the SDE performance, are experimentally studied. Reliability of MEA preparation process is verified through repeating electrolysis, optimized parameters of the MEA preparation process are obtained. Additionally, the effects of SDE performance to electrolysis conditions are clarified. Finally, a cell voltage empirical formula is determined with trial-and-error method. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.