Recently, the dynamic process of regional eco-economic system development has become the hot spot of academic research. Although some models were used to estimate the sustainability of regional eco-economic system, a comprehensive and dynamic index model has not been built yet. The evolution of regional eco-economic system is a dynamic and spiral development process from low-level combination to high-level harmonious coupling state, which is propelled by interaction and mutual influence between Resource-Environment subsystem and Economy-Society subsystem. The aims of regional eco-economic system development are to enhance ecology and economy, and to balance the limitless demand of Economy-Society subsystem and limited supply of Resource-Environment subsystem as well. The regional eco-economic system development is featured by metabolic process through the exchange of materials, energy and information between Resource-Environment subsystem and Economy-Society subsystem. The Yellow River Delta has entered a new period of fast construction and rapid development, since the High Efficiency Eco-economic Zone Plan in Yellow River Delta was implemented in 2006. Though there are abundant resources such as uncultivated land, salt and petroleum, the eco-environment in the Delta is very vulnerable. The large-scale resource exploitation will lead to resource damages or environmental pollution. In order to minimize the influence from economic and social activities, the Circular Economy mode would be a favorable developing strategy for the Yellow River Delta. The coupling state of regional eco-economic system has a decisive effect on the pattern and pace of sustainable development. Based on the General System Theory, a processing model of regional eco-economic system is built up in this paper. The coupling degree of the processes and tendency of regional eco-economic system is examined by the processing coupling model. Data and materials were collected from Dongying Statistical Yearbook 1991-2008, land use investigation by the Ministry of Land and Resources of China and Remote Sensing images interpreted by Data Center for Resources and Environmental Sciences Chinese Academy of Sciences (RESDC). The research finds include: Both of the index of Resource-Environment subsystem (f(en)) and the index of Economy-Society subsystem (f(el)) increased from 1990 to 2007. It indicated that the capabilities of resources supplies and environmental adjustment improved dramatically, and both economic and social progresses made remarkable achievements. Furthermore, the interaction between Resource-Environment subsystem and Economy-Society subsystem is entering a new phase of harmonious and interactive development as a whole. The coupling indices increased from 1990 to 2001 and then decreased from 2001 to 2007, which experienced a process of from inharmonious to concerted coupling. Based on the Trend extrapolation Method, the coupling degree will reach 45° in 2019, the optimal coupling point. However, the coupling state is still at a lower harmonious state, since the level of GDP per capita and urbanization at this area is lower than other developed coastal regions. To achieve a higher harmonious level and coordinate the progresses of ecological economization and economic ecologization, the High Efficient Eco-economic Zone Plan should be strictly implemented.