It is in a transition period of Chinese economic development. More attention has been paid to economic growth, but less attention to social development, environmental and resources protection. In order to improve this situation, it should focus on the coordinated development of regional system, including economic, social, population, resource and environmental subsystems. Under the guidance of scientific development, the coordinated development of regional system has achieved significant results. However, there are quite a lot of problems in different region, especially in inter-provincial border areas. Huai-hai Economic zone is a typical case. It covers north of Jiangsu, South of Shandong, and North of Anhui and East of Henan province, including 20 cities. Based on the evaluation criteria of regional coordinated development, and index system. Through analyzing its changes of coordination degree from 1950 to 2006 years, the following conclusions are reached. Firstly, the coordination degree is almost the type of basic coordination and comparative coordination. So, more attention should be paid to advanced-level coordinated development. Secondly, the type of the coordination degree evolutes from one stage to another. That is, the type of the regional system's coordinated development evolutes from low-level of non-coordination stage to advanced-level of coordination stage. Thirdly, the type of the city's coordinated development is clearly different in different provinces. The coordinated development of the cities in Jiangsu and Shandong province is of a characteristic of spiral development, while the coordinated development of the cities in Anhui and Henan province is at a relatively backward situation. The subsystems of economy, societyl, population, resources and environment not only conflict with each other, but also coordinate with each other. Through analyzing the relationship among these subsystems, Huai-hai Economic Zone trise to realize coordinated development quickly. And the integration of the regional subsystems is an important condition to achieve coordinated development of regional system.