The competitive adsorption behavior of CO and H-2 molecules on FeO surface in the reduction process was investigated by TG (thermogravimetry) experiments and MD (molecular dynamics) simulation. The model based on the Langmuir adsorption equations was built to describe the adsorption ability of CO and H-2 molecules on the FeO surface. The results show that: oxygen atoms cooperate with iron atoms to have influences on the adsorption ability of CO molecules. When the Fe mole fraction is higher than the critical value of 0.57, the governed factor of carbon monoxide's adsorption is converted from oxygen atoms to iron atoms, but the hydrogen's adsorption is only governed by oxygen atoms on the FeO surface. The experimental results is offered by the explanations that there exist a attractive force between carbon atoms and iron atoms and carbon monoxide could be spontaneously adsorbed on the iron shell of FeO surface while the adsorption of hydrogen on the iron shell is unstable. The high temperature will weaken strength of carbon monoxide's adsorption because of a negative effect on the adsorption energy. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.