To explore the potential for energy conservation and emission reduction in the blast furnace process technology of the steel industry, this study selected six advanced energy – saving and emission – reduction technologies for the blast furnace process in the steel industry as research subjects. An extended Conservation Supply Curve (CSC) model was constructed. In combination with the cost – benefit analysis method, three indicators, namely “unit energy-saving cost of technology-net present value – internal rate of return”, were selected. Based on the TOPSIS evaluation method, the technical feasibility was analyzed from the dual perspectives of technical energy-saving potential and enterprise benefits, achieving a collaborative evaluation of the economic feasibility and environmental benefits of extreme energy-efficiency technologies and providing a quantitative basis for steel enterprises to select technological routes. The results show that the extreme energy-efficiency technologies with higher comprehensive scores are ranked as follows: the automatic combustion and thermal equalization technology of blast furnace hot stoves, the dual pre-heating technology of air and gas for hot stoves, and the oxygen-enriched combustion technology for hot stoves.