Thirty years of reform and opening up,China's rapid economic development in the Pearl River Delta and Pearl River Delta region,which is closely related to the development of manufacturing industry.Then which cities, manufacturing industries are mone pwfessional in the Pearl River Delta? which cities manufacturing industries are more diverse? And what influence that manufacturing industry specialization and diversification could have? These issues are the starting point of this paper,their answer has also formed the main result of the paper.This paper mainly uses nine Pearl River Delta city volume changes between 1978 and 2010,industry specialization and diversification,between each industry distribution,analysis of the city's relative specialization and relative diversity index,probing into Pearl River Delta industrial specialization,diversification and other factors on City industry growth. <<