Abstract: Urban social spatial structure is an important content of urban social geography. Macroscopic economic, political and social systems are the foundation of the formation of urban social space; changes of economic, political and social systems contribute to the reconstruction of urban social space. In order to understand long time-scale transformation of the urban social system in China and impact on the changes of urban social spatial structure, this paper depicts the evolutional process of Changchun's social spatial structure in the 20th century. In recent hundred years, Changchun's social system has experienced three periods, including colonialism, socialist planned economy after 1949, and transition period of socialist market economy. Using historical data and statistics from these different periods, based on historical analysis and factor analysis, this paper describes the social spatial types in different periods and reveals evolutional characteristics of the social spatial structure through combined qualitative and quantitative analysis. In colonialism period, affected by Japanese colonial power, four social spatial types emerged, including senior Puppet Manchukuo officers areas, Japanese residential areas, national business areas and China's poor farmers residential areas. In socialist planned economy period, the types of social areas were relatively simple and homogeneous, mainly including salariat areas, intellectual areas and workers areas. In the transition period of socialist market economy, the social spatial types were multiple and heterogeneous. Six social areas were formed including general salariat areas, high-density and crowded old city, concentrated areas of manufacturing workers, areas of high-income population, concentrated areas of migrant population, and areas of agricultural population. In the three different historical stages, Changchun's social space has tripartite different characteristics such as national isolation, units differentiation, and fragmentation, respectively, corresponding to the background of diverse political, economy, and social systems. The external political and military forces were important reasons for national isolation and spatial differentiation in colonialism period. Affected by unit system and functional layout of urban planning, residential spatial differences of employment groups working in different units had become the main reason forsocial spatial differentiation in socialist planned economy period. In transitioning to socialist market economy, due to the development of diversified liberalism market economy, transition of urban function, and motivation of housing market, the polarization and differentiation of social groups have become prominent in terms of wage income, social status and residential location choice. As a result, the differentiation and fragmentation of social space emerged and intensified constantly. In a word, social system and its change always impact urban social spatial space in spite of different political, economic and social systems in the different periods. With the evolution of urban space, the influence would produce spatially overlapping and cumulative effects, which would restructure urban social spatial morphology. In conclusion, this paper mainly reflects the production and reproduction of urban social space in China's modern times with different political, economy, and social systems in the background. In addition, this paper attempts to summarize a theoretical framework of the evolution process and mechanism of urban social spatial structure on the basis of institutional change in China. In the foreseeable future, this theoretical framework will be beneficial to providing a dynamic analysis case for the literature of urban social spatial structure.

Key words: Changchun City, colonialism, evolution, planned economy, transition, urban social spatial structure