Decarbonization of the steel industry is of great significance to support China’s "dual carbon" goal. Increasing the proportion of lump ore into the furnace is an important measure to reduce the carbon emissions of blast furnace ironmaking, and how to reduce the adverse impact of high lump ore ratio on the blast furnace smelting process is the key limiting link in the application of this process. The effects of lump ore ratio, nut coke mixing amount, and nut coke addition method on the soft melt performance of the comprehensive charge are investigated by a soft melt test. The results show that with the increase of lump ore ratio from 12% to 24% (lump ore completely replaces pellets), the softening onset temperature and melting onset temperature decrease by 60 ℃ and 39 ℃, respectively, the softening interval increases significantly, the dripping temperature decreases, and the position of the soft melt zone increases. The widening of the soft melting interval leads to a further increase in the S value to 195.29 kPa·℃, which is an increase of more than 30%, that is, the soft melt performance of the charge gradually deteriorates. Under the condition of mixed 4 g of nut coke(28.6 kg/t molten iron), the melting start temperature is increased from 1 397 ℃ to 1 440 ℃, and the S value is decreased from 185.16 kPa·℃ to 46.61 kPa·℃, which is reduced by about 75%, and the air permeability of the material layer is significantly improved,that is, the soft melt performance of the charge is significantly improved. However,further increasing the amount of mixing is not very effective, and the effect of outside mixing is better than that of layering. When the temperature exceeds the melting start temperature(T_s), the consumption of nut coke becomes obvious,and its consumption rate is about 40% during the whole soft melting process. The results can provide a reference for the efficient smelting of blast furnace under the structure of high lump ore ratio charge.