Abstract: Based on sustainable land use, this paper uses the improved TOPSIS method to evaluate the land use multi-functional changes and functional disturbances in Lanzhou City, Gansu Province, China from 1995 to 2015 to illustrate the characteristics and laws of those changes. The results can be summarized as follows: (1) The total land use function in Lanzhou shows a rising trend. The harmony of land use functions had experienced a decline at the beginning and a rise thereafter, and the functions had become increasingly diversified and the functional focus has been changed from social function to economic function. (2) Both economic and social functions had entered a period of rapid improvement, while the ecological function has experienced a gradual decline and followed by a slow rise. (3) The degree of economic and social dysfunction had been decreased over time, while the degree of ecological dysfunction has been on the rise and become the most obstacle of land use functions. Based on the analysis, we suggest that the focus of land use in Lanzhou in the future should be paid on uplifting the ecological function and improving the agricultural production and cultural leisure functions which are the letdowns in the economic and social functions as well as improving the coordination between land use functions．

Key words: land use, multi-functional land use, improved TOPSIS, barrier degree, Lanzhou City