The cities’ economic power has been quantified by using principal component analysis in Changjiang Middle Reaches Megalopolis，it analyzes the evolution rules and characteristics of urban agglomerationthrough transverse and lengthways contrast；using the panel model analysis method and regression analysis of panel data. Set up a regression model based on various economic indicators of 2005-2015 in Changjiang Middle Reaches Megalopolis，the model analyzes the impact on the economic power from the economic base，industrial sructure，openness，financial enviroment and the input of technology education.