Global warming has become an indisputable fact.People get to know that the mode of production relying on over consuming energy,the mode of economic development at the expense of the environment and the excessive spending life style should be fundamentally changed.Cities are not only the carrier of industry,construction,transportation,but also the main source of high energy consumption and high carbon emissions.In order to deal with the challenge of global warming,we need to change the traditional pattern of urban development.The paper first adopts IPCC energy conversion model to test the carbon emissions in Nanjing,then choses indexes including population,GDP,per capita GDP,population urbanization rate,coefficient of diversified industrial structure(ESD),coefficient of diversified energy consumption structure(ESCD) and energy intensity of Nanjing as the comparison sequences,specifies Nanjing's CO₂ emissions as a reference sequence,then calculates and sorts the association degree of the comparison sequences with the reference sequence using grey correlation model.The result shows that according to the correlation with carbon emissions in Nanjing,the descending order should be ESD,population,urbanization rate,ECSD,energy intensity,per capita GDP,and GDP.It's in line with the data provided by the research that industrial emission for production holds over 50% because of the wide use of fossil energy.The potential contribution of related indexes to Nanjing's building of low-carbon city are elaborated,hence some suggestions are put forward for policy makers.