Abstract: The distribution of reducing gas in the shaft furnace of COREX-3000 influences directly the gas utilization ratio, the metallization degree of directly reduced iron and the burden descent. The charging of burden is the main means for regulating the gas flow distribution. A mathematical simulation model of burden distribution for COREX-3000 shaft was developed by discrete element method, and the model parameters were determined. The change of particles velocity and particles distribution in the process of burden charging, as well as the surface profile and inner structure of the bed, were analyzed at particulate-scale. The simulation results show that the small radius, heavy mineral particles tend to go through the surface layer consisted of the light and large size of fuel particles, thus it seems to make large particles enriched in the surface of heap.