The invention provides a method for using iron ore powder in an ironmaking system. The method comprises the steps: screening, burdening, mixing, secondarily mixing and pelletizing, distributing, igniting, sintering, crushing and cooling, screening, and detecting an index of a sintering ore, wherein screening comprises two passes of screening of iron ore powder to obtain iron ore powder with three particle sizes of more than 20 mm, 8-20 mm and less than 8 mm, wherein the iron ore powder with the particle size of more than 20 mm is supplied to a blast furnace as a lump ore, iron ore powder with the particle size of less than 8 mm participates in conventional sintering and burdening, and the iron ore powder with the particle size of 8-20 mm is sent to be distributed and sintered after being mixed with other pelletized materials. The invention provides a method for using the iron ore powder in the ironmaking system. The iron ore powder of different particle sizes can be maximally utilized, and the production benefit of the blast furnace and sintering is increased.