As a pillar industry of the national economy, the steel industry is facing the challenge of high carbon emissions. The current situation of carbon emissions in the steel industry is summarized, the characteristics of different steel manufacturing processes and the carbon emission intensity under different processes are analysed; low - carbon metallurgical projects such as ULCOS in the European Union, COURSE 50 in Japan, POSCO in South Korea are introduced, the principles, advantages and disadvantages of the main CO₂ capture technologies and the application of CO₂ in the whole process of iron and steel smelting are comparatively analysed in detail, and the application effect and potential of CO₂ in the whole process of steel smelting are confirmed; the research progress of the application of CO₂ in blast furnace, steel furnace, electric arc furnace, converter, refining and continuous casting are elaborated, the properties of CO₂ at steelmaking temperature are analyzed from the perspectives of thermodynamics and kinetics, and it is pointed out that CO₂ can be used as an oxidant in the steelmaking process and it has the advantages of reducing carbon emission and improving the quality of molten steel. CO₂ capture and its resource utilization are of great significance for the green and low - carbon production of the steel industry, and the capture and utilization technology of CO₂ should be further studied in the future, and its application in the whole process of steel smelting should be promoted to achieve the sustainable development of the steel industry.