In the era of economic globalization, the concept of Economic Polarized Area comes into being as an effective vehicle to agglomerate the economic elements and sustain the economic lifeline of the region. Based on the region's specific development mode and construction form the concept is working in such a way that it will contribute to guide the economic development of the country and will play an important role in competing with other regions or countries in the world. Due to the high speed development of the last 30 years, the Yangtze Delta Region starts to show the features of Economic Polarized Area. But, compared with other world-class Economic Polarized Area, the economic strength and the ability of the Yangtze Delta Region to drive the country's economic development is still very low and the competitive power is still very limited. Expanding the scope of the Economic Polarized Area of the Yangtze Delta may extend the economic hinterland of the core area of the Yangtze Delta Region, and will lighten the pressures from the limited resource and the burden of environmental pollution. With regard to the reasonable scope of the Yangtze Delta Region, there are different opinions and controversial arguments in political and academic circles. Starting from the idea of increasing the competitive power and improving the economic strength of the Yangtze Delta Region, the paper firstly discusses the requirements to become a world-class Economic Polarized Area. In a second step an analysis of functional complementation and economic collaboration between the cities of an "extended" Yangtze Delta Region has been carried out by in particular considering the feasibility of integrating these "newly included" cities. The final result of the study is, that the Region should be expanded from the number of 16 cities to 37 cities, and the appended cities should be divided into two categories: Wenzhou, Jinhua, Yancheng, Huaian, Ma'anshan, Wuhu, Tongling, Chaohu, Hefei, Chuzhou, and Xuancheng should be taken as Preferred Extending Area, and Suqian, Xuzhou, Lianyungang, Lishui, Quzhou, Chizhou, Anqing, Bengbu, Huangshan, and Suzhou should be taken as Retained Qualification Area.