Abstract: Given the incomplete utilization of enthalpy heat in a two-step smelting reduction process, gas reforming was studied by using numerical simulation. Under fixed gas temperature and flux, carbon consumption increased with increasing of carbon-based packed bed height and decreasing carbon particle size, while water vapor consumption decreased with carbon-based packed bed height and decreasing carbon particle size; extent of oxidation of gas in the COREX decreased from 0.10 to 0.065, while oxidation of gas in the HIsmelt decreased from 0.625 to 0.223, and the heat was fully utilized.