Abstract: In order to explore the feasibility of adding high reactive semi-coke to blast furnace instead of some coke, the cold and hot permeability tests of the coke and semi-coke after gasification were taken to obtain the parameters of the liquid flow rate, the amount of drop and retention in the coke bed. The results showed that the highly reactive semi-coke could protect the coke during the gasification of the upper part of the blast furnace. In the cold drop experiment, with the increase of the proportion of the semi-coke, the drop rate of the liquid slowed down, and the drop amount decreased by 16.8%. When the size of the semi-coke increased to 20~23 mm, the drop amount of the liquid increased by about 20%; In the hot slag retention experiment, under the condition of large particle size, the slag retention was reduced by about 50%, with the liquid permeability improved. Considering the gasification of the upper part of the blast furnace and the permeability of its lower part, adding a small amount of large diameter reactive semi-coke could reduce the gasification loss of coke, maintain its strength relatively, stabilize the liquid permeability of burden, and achieve the purpose of saving the resources of high-quality metallurgical coke.