B ased on the data at the level of sub-district of the third population census in 1982 and the fifth one in 2000, the authors try to analyze the characteristics of socio-spatial differentiation in B eijing M etropolitan A rea and calculate several indices, including the inform ation entropy, the absolute differentiation index and the relative one, and the index of residential segregation, to indicate the features of the restructuring of socio-spatial differentiation in B eijing M etropolitan A rea.The authors prove that the scale of sub-districts is still an im portant spatial unit for studying urban socio-spatial structure in China w ith enough maneuverability. The analysis of the 2000 census data show s both the pattern of socio-spatial differentiation of each kind of residential population, including density of residential population,m igrant population,fam ily size,old people,population of each kind of educational level,and the minorities,and that of the em ploym ent and housing status under the background of suburbanization and the transition of urban econom y in Beijing M etropolitan Area. The authors find out that the degree of socio-spatial differentiation of Beijing Metropolitan Area in most social indices decreased in the period 1982-2000, except for several indices including the old, sex ratio, family size and the farm ers on the basis of the absolute differentiation m odel. In the sam e period, on the basis of the relative differentiation m odel, they find out that the spatial distribution of m igrant population,the m inorities,population w ith higher education level, and the em ploym ent population of the secondary and the tertiary industries tend to accord w ith the spatial pattern of total urban population, w hile the old, the illiterate and the farm ers do not. From 1982 to 2000, the residential m ixture of m ost dem ographic indices tend to be increasing, w hile that of the old, the m igrants and the farm ers does not.G enerally speaking,the change of the inform ation entropy indicates that urban social spatial structure tend to be m ore com plex w ith m ore and m ore heterogeneity, w hich accords w ith the findings of sim ilar research on the basis of the analysis of B eijing's social areas.M ost im portant of all,by contrast,the analysis by differentiation m odels show us m ore details about urban socio-spatial differentiation and its restructuring, w hich can also be indicated from the restructuring of the relationship betw een the socio-spatial differentiation and the distance from the city center. Finally, the authors put forw ard a theoretical fram ew ork based on the evolution of system , m arket and culture in order to explain the restructuring of socio-spatial differentiation of Beijing Metropolitan Area in the transition period.