| The study on the change of land-use and land-cover is a core for studies on the global changes in recent years. The research on the spatial-temporal change of LUCC is significantly important for better understanding LUCC and environmental management for sustainable development.The steppe on Inner Mongolia Plateau is much representative. It is the main component of Eurasia steppe. In this paper, the Baiyinxile Ranch was selected as the study area. The land cover maps in 1987 and 2004 were produced by using of Landsat TM dada, the land cover map in 1965 was made by digitalizing the vegetation map produced by field survey in 1965. Based on the three maps, the changes of the land-cover and its pattern in the Baiyinxile Ranch from 1965 to 2004 were analyzed. The results indicate that the land cover in the study area had changed greatly, the area of Stipa grandis-Leymus Chinesis-memic-xeric-forbs steppe decreased from 9.99% to 7.82%.With the increase of human' activity, the landscape fragmentation had become , the value of density index in 1965, 1987 and 2004 was respectively 0.232, 0.430 and 0.510, showing a increasing trend; the value of CONTAG decreased from 61.77% in 1965 to 54.61% in 2004, also indicating the study area was in a trend of the landscape fragmentation.Combing landsat-TM data and vegetation investigation in the field, we established a model of steppe aboveground biomass estimation. The aboveground biomass of steppe in the study area in middle August 2004 was estimated. In 2004, 24.12% of the study area was heavily degraded steppe, and 10.70% of study area was slightly degraded steppe. The reasonable stocking capacity was also determined. The result showed that the average reasonable grazing intensity was 43 standard sheep unit/km2, but the actual grazing intensity was 86 standard sheepunit/km2 in 2003. The results indicate reducing livestock's numbers is the absolutely necessary in the restoration of degenerated steppe.
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