A thermodynamic analysis of hydrogen production from oxidative steam reforming (OSR) of methanol has been carried out by a Gibbs free energy minimization method. The equilibrium yields of hydrogen, carbon monoxide, methane and coke as a function of H2O/MeOH ratio (0.0-10.0), O-2/MeOH ratio (0.0-1.0), and temperature (200 degrees C, 400 degrees C, 600 degrees C, 800 degrees C) at 0.1 MPa are investigated. Methanol can be fully converted at any H2O/MeOH and O2/MeOH ratio in the condition range evaluated. Methane is the main product at low temperatures (200 degrees C, 400 degrees C), while hydrogen and carbon monoxide become dominant products with the increase of the temperature. 600 degrees C is favorable for hydrogen production at which the highest hydrogen yield appears. Carbon monoxide yield increases monotonically with the increase of the temperature and shows its maximum at 800 degrees C. An increase of the H2O/MeOH ratio leads to a preference for hydrogen production as well as an inhibition of the formation of carbon monoxide, methane and coke. The major contribution of adding oxygen is lowering the energy supply and suppressing the potential of coke formation at low H2O/MeOH ratio. However, the total oxidation of methanol tends to dominant in this case. For the purpose of producing hydrogen-rich gas, no oxygen addition is preferred. The favorable operation window is obtained as 600 degrees C, H2O/MeOH ratio = 6.0-8.0 and O-2/MeOH ratio = 0. Under this optimal condition, 2.77-2.84 mol/mol methanol hydrogen yield and 0.13-0.17 mol/mol methanol carbon monoxide yield with trace amount methane (0.0070-0.017 mol/mol methanol) can be achieved without the risk of carbon deposition. (C) 2012 Elsevier Ltd. All rights reserved.