Low-carbon operation, especially low-coke-rate operation, is very important for low CO 2 emission in blast furnace ironmaking. Maintaining the permeability of the cohesive zone is required under lowcoke operation of the blast furnace. The cohesive zone and permeability are determined by the softening and melting properties of the burden. In this study, the effect of reduction degree on the cohesive zone and permeability was investigated by using different reduction degree mixed burdens. The experimental results showed that as the reduction degree increased, the thickness of the cohesive zone decreased, the position of the cohesive zone moved downward, and the permeability of the mixed burden layer was significantly improved. The weight of the droplet and the carbon content of iron in the droplet decreased with the increase of reduction degree. The results of experiments provided an important guidance for improving the permeability of the mixed burden layer in low-coke operation of the blast furnace.