Abstract: Take Yangtze River Delta Urban Agglomeration as an example, the main indexes of new urbanization and ecological capacity were analyzed and a new coupling model was constructed. We aimed to construct mechanism based on under Earth Ethicsin and Main Functional Region. The research provided a practical reference for the sustainable development of new urbanization and ecological environment. First, the coupling of the new urbanization and ecological environment was between 0466 and 0667, implying that the whole was in the transition period between the antagonistic stage and breakingin stage. Second, the coordination of the new urbanization and ecological environment was between 0048 to 0338, implying that the overall level was in low coordination. Third, All of the cities in Yangtze River Delta Agglomeration were classified into three types: New urbanizationecological environment “breakingin stage”(Shaoxing, Zhenjiang, Changzhou, Hangzhou, Taizhou), New urbanizationecological environment “antagonistic stage”(Shanghai, Jiaxing, Nantong, Taizhou, Yangzhou, Ningbo, Zhoushan) and New urbanizationecological environment “moderate coordination stage”(Nanjing, Suzhou, Wuxi, Huzhou). Under the guidance of Leopold’s Earth Ethics, this paper puts forward a new mechanism to promote the synergetic mechanism of new urbanization and ecological capacity, and provide a new perspective for studying and constructing the synergistic mechanism of new urbanization and ecological carrying capacity