The characteristics of methane autothermal reforming to generate hydrogen were studied with thermodynamic equilibrium constant method. Results show that the methane steam reforming reaction is prone to backward at low temperature, and there is an inflection point temperature that the reaction turns forward. When steam methane molar ratio is 2, the inflection point temperature increases with raising air methane molar ratio. When air methane molar ratio is 1, the inflection point temperature maintains between 700 and 800 K. Hydrogen yield increases firstly and then decreases with elevated temperature. The increase of air methane molar ratio leads to a lower hydrogen production when temperature exceeds 1000 K. Increasing steam methane molar ratio promotes the hydrogen production. Methane autothermal reforming occurs much more easily when temperature keeps at 1000 K and the molar ratio of air-methane and steam-methane is 1 and 2 respectively. Changing the steam-methane molar ratio can regulate H-2/CO molar ratio. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.