Thermodynamic analysis of steam reforming of methane has been studied by method of Gibbs free energy minimization for hydrogen or syngas production in the ranges of steam to methane from 0.5 to 3, reaction pressure from 1 to 50 bar and operative temperature from 600 to 1200 K. The important considered parameters were methane conversion, selectivity of hydrogen, selectivity of carbon monoxide, hydrogen per carbon monoxide ratio, steam per carbon monoxide ratio and coke formation. Furthermore, this study investigates on the application of the statistical models in steam reforming of methane. The effect of parameters was determined via an orthogonal second order design. (C) 2015 Published by Elsevier Ltd.