Abstract: Through analyzing design features of the cooling system above the hearth in TISCO 4 350 m³ blast furnace(BF),the effect of gas flow distribution on the heat load of the blast furnace was studied in the case of high pulverized coal injection rate and high yield.The results of No.5 blast furnace were presented.The value of edge gas flow index W should be controlled at around 0.55,the value of center gas flow index Z should be controlled at around 8.8,and the heat load on the belly and the bosh of the blast furnace is relatively stable but in the upper part of the stack is bad.There is a potential to reduce the heat load of No.5 blast furnace.When the heat load is controlled in the range of 10 to 120 GJ·h^-1,the 4 350 m³ blast furnace can still be stably operated.