As the largest energy consuming manufacturing sector and one of the most important sources of carbon dioxide(CO2)emissions,the China’s iron and steel industry has paid attention to the study of changing trend and influencing factors of CO2 emissions from energy use.The logarithmic mean Divisia index(LMDI)technique is used to decompose total change in CO2 emissions into four factors:emission factor effect,energy structure effect,energy consumption effect,and steel production effect.The results show that the steel production effect is the major factor which is responsible for the rise in CO2 emissions;whereas the energy consumption effect contributes most to the reduction in CO2 emissions.And the emission factor effect makes a weak negative contribution to the increase of CO2 emissions.To find out the detailed relationship between change in energy consumption or steel production and change in CO2 emissions,the correlation equations are also proposed. As the largest energy consuming manufacturing sector and one of the most important sources of carbon dioxide (CO2) emissions, the China’s iron and steel industry has paid attention to the study of changing trend and influencing factors of CO2 emissions from energy use. Logarithmic mean Divisia index (LMDI) technique is used to decompose total change in CO2 emissions into four factors: emission factor effect, energy structure effect, energy consumption effect, and steel production effect. The results show that the steel production effect is the major factor which is responsible for the rise in CO2 emissions; while the energy consumption effect contributes most to the reduction in CO2 emissions. And the emission factor effect makes a weak negative contribution to the increase CO2 emissions. To find out the detailed relationship between change in energy consumption or steel production and change in CO2 emissions, the correlation equations are also proposed.