Abstract: As an important assessment factor of urban development and ecological environment, impervious surface area (ISA) is of great significance in ensuring ecological health and sustainable urban development. In this paper, Ordos is taken as the study area and ISA information from 1990-2019 is extracted by fusing multi-temporal Landsat and nighttime lighting data (NTL), and the spatial and temporal evolution patterns are analyzed using the center of gravity analysis method, standard deviation ellipse theory (SDE) and landscape index theory (LI). The results show that:①From 1990 to 2019, the ISA of the Ordos city has experienced rapid expansion; the coverage of ISA in the northeast is higher than that in the southwest; the expansion pattern of ISA is:generally characterized by "outward expansion-inward encryption". ②The expansion rate in the northeast is slowing down, while the expansion rate in the southwest is increasing. ③ The directionality of ISA expansion is decreasing; the direction of ISA expansion is changing from "northeast-southwest" to "east-west". ④The number of patches increases, the fragmentation of edge patches increases, the connectivity between urban and suburban areas increases, and the city tends to expand to the surrounding suburbs. This study is a useful reference for further understanding the relationship between urban ecological health and sustainable urban development.

Key words: multi-temporal remote sensing, impervious surface area, GIS technology, landscape index, Ordos