Abstract: Based on remote image and GIS technology, this paper analyzed the relationships between land use system and natural topographic factors such as elevation, slope, and river system in Xishuangbanna. The results showed that the land use system in the study region was dominated by forestland, cropland and grassland. The area of forestland was 13 420 km², accounting for 74% of the total, and that of cropland and grassland was 3 251 km² and 2 332 km², accounting for 13% and 18% of the total, respectively. The areas of these three land use types varied with elevation in singlepeaked curve. Forestland mainly distributed around the elevation of 1 000~1 200 m, while cropland and grassland centralized at the elevation of 900 m. Urban land and cropland, which were greatly influenced by human activity, had lower slope index than forestland and grassland. Besides elevation and slope, river system in valley had effects on land use condition. With increasing buffer distance in valley, a strong spatial pattern of land use type was presented, i.e., cropland, urban land and unused land concentrated greatly adjacent to water, while forestland and grassland were far away from valley. A landscape with relatively primary status, which was comprised of forestland as matrix, river as corridor, and cropland as patch, would come into being.

Key words: Groundwater environment, Oil pollutant, Modelling analysis