Abstract: Open space plays an important role in the improvement of land value, ecological environment and urban spatial structure. The research on open space has become a hotspot. Based on the land utilization present situation chart of 1995, 2003 and 2008, the remote sensing images of Changchun City, Jilin Province, China of 2013, by using ArcGIS technology, and in combination with the gravity research methods of distribution center, the extended mode determination index and buffer analysis method, this paper analyzed the spatial-temporal evolution characteristics and dynamic mechanism of the open space in Changchun. Results show as follows:(1) the gravity center of open space presented volatile clearly, which was located at the southeast during 1995-2003, whereas located at the northeast during 2003-2008 and in the northwest during 2008-2013. After a large space-transition, Changchun stepped into a relatively stable developing stage, and the integrated space layout of open space was optimized.(2) The overall extension mode of open space was given priority to "enclave type + filling type", but different stages had different characteristics. Open space in the central urban area was constantly replaced by living space and service space during 1995-2003, and the extension mode of the open space was dominated by shaft extension and auxiliary by cohesive filling during 2003-2008, while dominated by enclave expansion and auxiliary by shaft extension during 2008-2014;(3) Local agglomeration and overall diffusion was the evolution characteristics of the open space, but it was still presented the structure of "one center"; however, after the suburbanization developments for many years, it presented the evolution trend to "multi-center" structure. On the basis of the above research results, this paper regards the natural conditions, establishment and rapid development of development zones, single center-city space structure, the urban planning, and reform of land use system as the dynamic mechanism of the extension characteristics of the open space in Changchun. This paper broke the pattern of previous research which either study on the qualitative analysis or using the accessibility measure to the quantitative analysis, providing a new way to research on the open space. This paper could provide the reference for the optimization of urban spatial structure and the development strategy of urban space.

Key words: open space, spatial-temporal evolution, dynamic mechanism, Changchun City