Since water allocation scheme in the Heihe River Basin (HRB) between Gansu Province and Inner Mongolia was executed after 2000, water use in the midstream in the HRB was limited by space-time restriction. Therefore, it is important to analyze the land use/cover change and driving force, and the problem of eco-environment. The results were as follows: 1) The land use structure changed greatly in the study area. From 1985 to 2000, farmland, woodland, residential and industrial land increased while grassland, water area and unused land decreased; from 2000 to 2005, farmland, residential and industrial land continued to increase, while the remaining land use types decreased. 2) Since the execution of the water allocation scheme in the HRB, the ecological environment deteriorated more quickly, the main reasons of which may be that the available water decreased and the farmland area increased quickly in such a short period. Grassland, woodland and water area decreased obviously, and the change ratios of grassland, woodland and water area were 2.14%, 7.36% and 3.69%, respectively. 3) From 1985 to 2000, the major patterns of land use change were mutual conversion of farmland and residential and industrial land, mutual conversion of farmland and unused land, the conversions of grassland to farmland; from 2000 to 2005, the major patterns of land use change were the conversions of unused land to farmland, mutual conversion of grassland and farmland. 4) There were obvious spatial differences in land use degree changes, and the greatest change took place in Ganzhou County. 5) The main forces of land use changes in the study area are population growth and economic development. However, the amount of the available water resources of the HRB influenced the land use changes more significantly after 2000.