中文摘要：

聚集是影响区域经济增长、城市规模及城市内部空间结构的重要因素之一。京津两城的发展战略对环渤海经济区域发展及空间结构调整起着至关重要的作用。然而，运用空间经济理论对京津城市发展及环渤海区域空间结构问题进行研究的文献较少，因此，在大北京集聚效应的背景下，首先分析了京津两城城市功能定位及环渤海区域规划所带来的问题；其次运用空间经济理论对集聚所产生的溢出效应、环渤海区域规划单中心与双中心城市发展战略、区域经济增长率等方面进行了详细研究。最后指出面对因聚集而使北京逐渐成长为环渤海区域“单中心”的局面，要尽快调整环渤海区域规划及空间布局，全力实施京津双中心城市发展战略。通过多渠道多方法，在增强北京技术及资本溢出效应（增加值）的同时，降低北京聚集引力，减缓外地资源（特别是天津）流失程度。

英文摘要：

Agglomeration is one of the most important factors influencing regional economic growth, city scale and the internal spatial structure of cities. The development strategy of Beijing and Tianjin plays an important role in the regional development of Bohai coastal economic zone and the change of spatial structure. However, studies on these topics are very limited. Therefore, based on the background of agglomeration effect of Beijing, the paper first analyzes urban function positioning of the two cities and the problems caused by the plan of Bohai coastal region; besides, a detailed analysis is made on the spillover effect, strategy of Bohai coastal region plan, and the growth single and double center urban development rate of regional economy by using spatial eco- nomic theory. The author finally points out that facing the situation of making Beijing to be the ＂single center＂ of the region because of agglomeration, the regional plan of Bohai coast and its spatial arrangement should be changed quickly, and more efforts should be done on implementing Beijing- Tianjin double center urban development strategy. While increasing the technical and capital overspill effect （ increasing the ~ value） of Beijing, the agglomeration of Beijing should be lowered down and the resource loss from other cities should be slowed down.