Abstract: Based on Landsat-TM and CBERS images of the Kaidu-Kongque River valley in 1990, 2000 and 2010, and with the aid of the GIS technology, dynamic changes in land use/cover and landscape pattern of the valley and causes of the changes in the recent 20 years were analyzed,  Results show:In 1990 — 2010, the changes in farmland, construction land and water wetlands were the most obvious, being at a rate of 4.76%, -1.61% and 1.45%, respectively, in annual mean, while the change in virgin land, the least, being at a rate of -0.29%; 8.71% of the grassland area and 1.73% of the virgin land transformed into farmland, 2.41% of the grassland into water surface or wetland and 54.74% of the construction land into waste land; Before the year of 2000 forest land decreased in area, being mainly transformed into farmland, while after that year, farmland and grassland were turned back into forest land, increasing the forest land in area; During the time period covered by the study, cultivated land and water surface/wetland tended to be concentrated in distribution and gradually became the dominant types of landscape in the study area; Before 2000 forest land distributed in fragments, but after 2000 it began to tend to be concentrated; during the period, grassland decreased in area and in landscape dominance as well; and as a result, the landscape pattern tended to be simple.  It is believed that it is mainly the continuous growing population and their activities for seeking economic profits that has caused farmland steadily diminishing in area in the valley, thus seriously threatening the eco-environment safety of the valley.

Key words: Kaidou-Kongque River valley, LUCC, landscape fragmentation