Abstract: The land use changes of Yilihe watershed of Xinjiang Autonomous Region was obtained by analyzing Landsat-TM data,which was with two period digital images taken in 1990 and 2000 respectively.The dynamics of the ecological environment quality caused by land use changes were evaluated by using the dominance value of landscape ecology and Costanza's method for evaluation of the world's ecosystem service.The results indicated that grasslands were the main landscape type in plain and hilly land of Yilihe watershed.From 1990 to 2000,the areas o f the water body,unused land and forestland declined,while the areas of the urban land,farmland and grassland expanded.The total degree of the predominance for the arable,unused and urban land increased form 33.4% to 38.3%.The adverse impacts were aggravated.Generally,the ecosystem service values of Yilihe watershed diminished by the land use change in the past ten years.The loss of ecosystem service values was around 4.4%,equaling to 6.38 ×107 US$.

Key words: Yilihe watershed, Yilihe watershed, Land use change, Landscape, Ecosystem, Service value