Abstract: In this paper, a mathematical model was developed for the hydrogen production of methane steam reforming under concentrated radiation based on a self-designed solar thermochemical reactor. The model that coupled conduction, convection, thermal radiation and chemical reaction kinetics was adopted to calculate the concentration, reaction rates and temperature of reactant and product in reactor and to investigate the effect of various operating parameters (porosity, gas inlet temperature, steam to methane ratio) on the conversion rate of methane. The research results showed that: Methane steam reforming reacts rapidly at the inlet of porous region. Along the reactor centerline, the reaction rate decreases due to the constant decrease of reactant concentration, which leads to the steady concentration and temperature of the mixed gas. The conversion rate of methane conversion increases as the increasing in porosity, gas inlet temperature and steam to methane ratio. The methane conversion rate was 96%, the hydrogen yield was 28% while the gas inlet temperature, porosity, steam to methane ratio and inlet velocity were 500 K, 0.75, 2.5 and 0.006 m/s, respectively. The research results have certain reference significance for parameter optimization for hydrogen production process of methane steam reforming.