Abstract: Based on the European Space Agency (ESA) Climate Change Initiative (CCI) Land cover products, this paper examines the land use/cover data of four years (2000, 2005, 2010 and 2015) for the Qaidam basin, and calculates the land use/cover type change matrix. Then, using the matrix, we evaluate the land use transfer priority direction and formulate a new land use grade index. The results show that in this basin, the main land use types were grassland and unused land, accounting for 51.6% and 44.9% of the basin, respectively. Water area, cropland and forestland were in a decreasing order of land cover proportion, and the proportion of residential land was the smallest. During the past 15 years, cropland, grassland and residential land areas have been increased, while unused land decreased, both in a monotonous trend. Of the transformation between different land use/cover types, the one between grassland and unused land was the largest, and it occurred mainly in the southwest of the basin and the Qilian mountains. The land use grade index of the Qaidam basin shows a continuing growth but in a small range, which means the change in land use/cover has been stable globally and sharp locally. The study provides an approach for land resource assessment, land use planning and sustainable management.

Key words: land use/cover, spatiotemporal variation, transfer matrix, land development grade, comprehensive grade index, Qaidam basin