Abstract: In this paper,a coupled mathematical model of temperature field and chemical reaction for producing ultrafine iron powder by carbon thermic reduction in a steel strip furnace is established.The simulation results are in good agreement with those of related experiments.Temperature distribution of material shows a a centrosymmetrical pattern. Temperature of upper and lower layer is higher than the center layer.The distribution law of reduction fraction is similar to the temperature distribution.The reduction degree of superfine iron powder is very sensitive to its thickness.The thinner the material layer,the higher the reduction degree.The average reduction degree of material with 25 mm thickness can reach 90%,while the material with 35 mm thickness is only 60% reduction degree.The reduction effect can be improved by prolonging the reaction time,but its effect on the reaction is smaller than the thickness.