Abstract: The Boundary analysis of megalopolis contains mainly the whole spatial boundaries and the internal structure boundaries. With the methods of principal component analysis and the cluster analysis, 238 counties, cities and districts in the Yangtze areas were explored of the structure features and spatial organizations of metropolis. Then the above two kinds of boundaries of the megalopolis is analyzed. The findings include, first, the whole spatial boundaries of the Yangtze Delta Region containing Suzhou, Wuxi, Ningbo, and Parts of Shanghai, Nanjing, Changzhou, Hangzhou, Zhenjiang, Yangzhou, Taizhou, Nantong, Shaoxing, Zhoushan. The second is that the megalopolis could be divided into three parts, the HuanTaihu Lake Regions with the core city of Shanghai, the Yangtze River Regions with the core city of Nanjing and the Hangzhou Bay Regions with the core city of Hangzhou and Ningbo. And the internal structure boundaries are locate at Dantu and JiaxingHuzhou. With the perspectives of Shanghai, the internal structures of the Yangtze Delta Regions have features of consenters and axes characters.

Key words: The Yangtze Delta Region, megalopolis, boundaries, metropolis, regional types, employment populace