The low-temperature waste heat of sintering cooling fume is used as the heat source of the organic Rankine cycle (ORC) system, the heat and economic model of the supercritical ORC system is established, and R134a is selected as the ORC working substance to study the influence of the inlet temperature and the pressure of the expander under the variable temperature heat source, as well as the condensing temperature of the working substance on the thermal economic performance of the system. The results show that the net output work of the system increases with the increase of the inlet temperature of the expander, and decreases with the increase of the inlet pressure of the expander and the condensing temperature of the working substance, but the heat transfer per unit temperature of the system decreases. When the thermal parameters of the system are constant, the larger the inlet temperature of the heat source, the greater the net output work of the system and the heat transfer per unit temperature will be. In the actual operation process, there are suitable heat source inlet temperature and thermal parameters of the system, so that the ORC system can obtain a larger net output work and a smaller heat transfer per unit temperature.