Because of the existence of foreign concessions during the late Qing dynasty，China gradually became a semi-colonial and semi-feudal society. However，the separation between foreign concessions and Chinese communities was in fact an outgrowth of the mode through which the thirteen hong merchants dealt with foreign traders under the Canton system. The significance of the separation of foreign and Chinese communities changed after the Opium War.Foreigners accepted and even cherished the status of being isolated from Chinese communities. After foreigners legalized their isolation and independence in China in accordance with treaty provisions，they continuously excluded Chinese legal rights and finally enjoyed absolute jurisdiction in the foreign concession areas. Therefore，the “golden enclosure” of the past became a specially privileged territory. The foreign concessions were thus despised by Chinese. It is worth noting that the foreign concessions were originally not colonies. Concessions experienced a process through which they became special colonial areas. This article aims to describe and analyze this process.