The blast furnace gas separated by a membrane has a higher content of combustible components. In order to explore its secondary utilization in blast furnace production, numerical simulation is conducted by means of Fluent software, and the model is verified by experimental data. Results show that when the blast furnace gas separated by the membrane is used as pulverized coal carrier gas for blast furnace injection, the gas velocity in the furnace evidently increases, and the maximum injection velocity can reach 279 m s−1. The formed high-temperature zone is closer to the centre of the blast furnace than those in the single injection of pulverized coal and in pulverized coal injection with general blast furnace gas as a carrier gas. The maximum temperature reaches 2610 K. Moreover, the pyrolysis reaction of pulverized coal is in advance, whereas the burnout rate of pulverized coal in the raceway presents a double-peak phenomenon. © 2020 Institute of Materials, Minerals and Mining.