Taking the Economic-Society-Environment system as an open system with complex structures, the coordinated relationship of the three subsystems is the prerequisite for regional sustainable development. Based on statistical data from 7 cities of the East China Sea and the established evaluation system, the comprehensive development level and the coupling coordinative degrees were analysed and predicted by R/S analysis. Comprehensive development slightly increased, with a few fluctuations in Jiaxing, and all of the coastal cities were in the run-in and improving stages for basically coordinative development, except Zhoushan, and were undergoing less imbalanced development in 1995, except Jiaxing, Taizhou, Wenzhou and Ningbo. And the comprehensive development of the cities in the eastern region was higher than the other, but the coupling and coordinative degree were both δ convergent, which illustrated the less regional difference in future. However, the trend of the comprehensive and coupling coordinative development of most coastal cities in future will be opposite to that from 1995 to 2015. To realize coupling coordinative development, it is necessary to take advantage of national strategies and their own competitive advantages and then build an eco-environmental collaborative governance alliance for resource saving and establishing an environmentally friendly society.