The unit iron consumption of sinter is a key index directly affecting the unit manufacturing cost of sinter. The influence factors of unit iron consumption of sinter is studied based on theoretical calculation and regression analysis, and the relationship between the unit iron consumption of sinter and the cost of raw material and fuel is studied by adjusting the proportion of limonite. The results show that the influence factors of unit iron consumption of sinter mainly include the burning loss value of mixed iron material, sinter basicity, sinter grade, SiO₂ mass fraction of sinter, FeO mass fraction of sinter, magnesia alumina ratio of sinter, and the proportion of limestone powder replacing calcareous quicklime powder. In fact, the unit iron consumption of sinter is not as low as possible, the sintered raw material and fuel cost are not the lowest when the unit iron consumption is the lowest. The best unit iron consumption of sinter is based on the lowest cost of raw materials and fuel.