This paper investigated the design of a porous medium-catalyst hybrid reformer for CO2 conversion by dry auto-thermal reforming, with emphasis on the reaction temperature distribution. In the reforming process, the reaction under excess enthalpy was explored by interface temperature measurement and infrared thermograph observation in a porous medium assisted packed-bed catalyst reactor. The hybrid design was arranged with the catalytic packed-bed in the downstream of the porous medium. In the arrangement, the reactants were preheated by internal heat recirculation and the conversion of CO2 was enhanced by the catalyst surface reaction. The temperature measurement at the axial position and infrared thermograph observation on the catalyst packed-bed indicated that the peak temperature could be stabilized and held at the interface of the PM and catalyst bed, which significantly improved the propagation and stability of the flame. This was helpful to the improvement of both thermal wave transfer and internal heat recirculation. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.