System simulation is carried out based on the COREX process simulation model. The coal consumption increases with the increasing of the volatile content in coal. The control of volatile in coal is an important step for COREX’s ironmaking. The coal consumption decreases with the increasing of the oxidation degree of raw gas out of the meltergasifier. The energy utilization ratio of COREX process increases with the increasing of the oxidation degree or decreasing of the temperature of raw gas out of the meltergasifier. The maximum value of the energy utilization ratio is just over 50%. The temperature of raw gas should have a much higher value, compared with the temperature of reducing gas entering shaft furnace. The requirement of using much more kinds of coal and facilitating process operations is a key reason.