From the functional sense

institutions import has made the spontaneous social stratification formalized and fixed

and labels the different stratum with clear identifiable character

from which an obvious stratum hierarchy can be visible. This research takes stratification of the floating population after importing system of resident permit in big cities as an example

and identifies another social stratifi- cation mechanism. As far as floating population concerns

the income gap among different stratum is not so significantly large; however

the social security

employ- ment

education chance and mobility upward vary largely across different sub-stra- tum. Re-stratification of stratum arises from some kind of interaction among insti- tutional factor

human capital

unit and social relations. Since the policy is not neu- tral

it seems unfair due to selective or discriminative character.