Green, efficient, and economic energy conversion from methane steam reforming requires understanding the reaction mechanism and intensification of reactor design to better convert energy at plant scale. On this research, a Ru catalytic wall reactor was prepared to conduct kinetic measurements of the methane steam reforming at low temperatures from 573 to 723 K, and then a microkinetic framework including, a basic reforming mechanism and computational load saving methods was developed. The products, were hydrogen and carbon dioxide, and the conversion of methane was promoted in high steam/carbon ratio (S/C) and low pressure region. Microkinetic simulation revealed that the methane decomposition. and activated water decomposition path were the main reaction pathways, OH*, CO*, H*, and O* were the main. intermediates; and small amount of intermediates on the catalyst surface during the reaction may promote methane, reforming in the high S/C and low pressure region. It was found that the overall reforming was controlled eqinvalently by kinetic and thermodynamic mechanisms, according to the calculated contribution of steps and intermediates on reaction progress.