This paper takes the Pearl River Delta Urban Agglomeration as a whole from macroscopic angle by breaking the administrative boundary, based on related theories on urban ubuffer area analysis of UGIS and GIS, as well as analysis on 30 km ubuffer areas of the entity line form and surface form on its inner core and axes zone (development axis and expanded surface) from promoting economic growth aspect, reaching the adjacent spatial visual effect between certain distance. The results show that (1) the ubuffer area scope of the expanding surface based on Guangzhou city includes the main city area of Dongguan, Foshan, Zhongshan and part of city area of Shenzhen and Zhuhai. (2) The ubuffer area scope of the development axis based on Guangzhou-Shenzhen railway includes nearly the whole administrative sphere of Dongguan and Shenzhen; the ubuffer area scope of development axis based on Guangzhou -Zhuhai highway includes the city area of Foshan, the whole Zhongshan city and Macao Special Administrative Region, part of Zhuhai administrative area, spreading to minor part of administrative area of Jiangmen and Dongguan. According to the regional scope which is eradiated and influenced by the ubuffer spatial sphere of the Pearl River Delta urban agglomerations core and axes region, this paper indicates from the viewpoint of geo-economics that as the future economic agglomerations, only by achieving the spatial combination of advantages and harmonious development can the Pearl River Delta achieve the conversion from unbalanced to relative balanced of regional economy in spatial distribution. Finally, the issues such as use of technology, choice of ubuffer distance and the further investigative direction are brought forward.