Abstract: The Yangtze River Delta of China, as a representative of regional economic development patterns, is increasingly becoming apparent, and has been China’s main strategic orientation of development in the 21st century to narrow the economic differences and achieve a balanced development.Meanwhile, the objective existence of such negative factors as the barriers due to administrative localizations, vicious competition between/among administrative regions are obstacles to joint cooperation between/among local governments.Administrative regionalization in the process of regional economic integration must reform and reconstruct.That means how to explore new regional management systems, to break the existing system of administrative fragmentation and to eliminate the negative factors, to create a new system design and to form a cross-regional but fully integrated with the crannies of public services and security system.The realization of regional equilibrium of the overall interests and the maximization and elimination of energy waste requires the adoption of new forms of governance between/among cities in the efficient allocation and integration of resources, so as to promote economic and social, cultural and various other factors and achieve the common development and prosperity.Based on the theoretic foundation of compound administration, regional regulation and common governance, in combination with the regional integration in the Yangtze River Delta as an example of the empirical study, we can explore how to reform and reconstruct the administrative regionalization in the process of regional economic integration by the reasonable arrangements of the intergovernmental institutions, systems, policies and the interests with the effort of local governments.