Small and medium -sized enterprises play a great role in the development o f regional economy.The transfer of these enterprises may re sult in imbalance between the region al economies,and further results in recession of the economy.This paper reviews th is phenomenon in other regions and countries.For the small and medium -sized enterprises in developed regions and countries,the cycle from development to transfer is 20years,and there are indications that the cycle tends to get shorter.The paper also makes a n analysis on the influence of these s mall and medium -sized enterprises on a re gion,studies the exception that the small and medium -sized enterprises in the Pearl River Delta areas of Guangd ong have kept growing for more than 20years,summarizes their developmen t experiences:grouping,categorizing,focusing and emphasizing the two ends,and points out the conditions u nder which a region can promote the develo pment of small and medium -sized ente rprises.