CO2 emission of the steel industry takes up a great proportion of the total emission of the world.It is necessary to reduce the CO2 intensity of steel products in order to save energy,protect the environment and keep a sustainable development in the steel industry.Based on the research of steel products life cycle inventory,those who conducted this research have focused on the analysis of CO2 emission factors and measures.Adopting the life cycle inventory model of a certain steelmaking site,together with the Tornado Chart,the researchers have identified significant factors,provided some explanation,and suggested some possible measures to reduce CO2 emission.The results have shown that the most important factors are the CO2 intensity of blast furnace gas (BFG),hot metal ratio of basic oxygen furnace (BOF) and the material utilization efficiency.Accordingly,some measures such as removing CO2 in BFG,decreasing the hot metal proportion in BOF,and improve material utilization efficiency in each process,may be taken to decrease CO2 emission.