Based on ArcGIS software, the Landsat5-TM remote sensing images of the Harten River basin in 1990, 2000 and 2010 were interpreted according to six land cover types. The results indicate that in the twenty years, the non-vegetation areas had decreased 2 192.37 km~2; in the high altitude upstream areas, grassland had obviously increased, with an increased area of 1 938.15 km~2, about 10% of the total basin area. As a result, the basin had significantly greened. The glacierized area had increased by 210.39 km~2, mainly due to glacier advancing. The non-vegetation land had mainly converted into the other five land types, with a rare reverse transformation. Conversion among high, medium and low coverage grasslands had usually be seen, but mostly one could see the low coverage grassland converted to medium and high coverage grasslands. The rising temperature and the increasing precipitation were the main factors of the land cover type change. Climate change has significantly improved the upstream vegetation. However, "The Water Diversion Project from Harten River to Danghe River", which will transfer 1.0*10~8 m~3 (interbasin) water from the Harten River to the Danghe River, would further affect the ecological system in the Dasugan Lake in the downstream area. It is necessary to strengthen monitoring and evaluation.