Through analyzing the reaction rate model of CO and H2 in the process of reducing pellets and based on experiments, the changes of resistance and reaction rate with the increase of temperature and reducibility is concluded respectively. Reaction rate model of gas mixture is concluded based on the two kinds of model. The proportion of internal diffusion resistance increases with the increase of temperature and reduction degree when pellets are reduced by carbon monoxide. Internal diffusion belongs to the rate control link when pellets are reduced by hydrogen. The reaction rate increases with temperature increasing while it decreases with carbon monoxide content increasing in the process of gas mixture reducing pellets when temperature is below 500 ℃. It will increase with the increase of the carbon monoxide concentration while temperature is over 500 ℃. Theoretical calculation value of gas mixture is consistent with the experimental results.
