[Objective] The characteristics of land use function transformation and ecological environment effect in Kaidu-Kongque River basin was studied to reveal the impact of land use transformation on regional ecological environment, in order to provide scientific reference for ecological environment protection and sustainable development. [Methods] Based on the remote sensing interpretation data of land use in Kaidu-Kongque River basin in 1990, 2000, 2010 and 2015, and according to the classification of the dominant functions of land use in “production-ecology-life”, the land use transfer matrix, regional eco-environmental quality index and the ecological contribution rate of land use transformation were used to quantitatively analyze the characteristics of land use transformation and spatial-temporal pattern in Kaidu-Kongque River basin.[Results] ① From 1990 to 2015, the transformation of land-use in Kaidu-Kongque River basin showed a rapid increase in production land and living land, and a rapid decrease in ecological land. ② From 1990 to 2000, the eco-environmental quality index of Kaidu-Kongque River basin decreased from 0.465 4 to 0.453 9, while rose to 0.455 9 from 2010 to 2015. The quality of ecological environment kept a relative balance, and showed a trend of decline first and then rise. ③ From 1990 to 2015, the ecological environment quality in the upper reaches of the Kaidu-Kongque River basin was relatively high, but there was a trend of deterioration. The ecological environment quality in the middle reaches of the basin was improved continuously, while the lower reaches of the basin were mainly low-quality areas. [Conclusion] The increase in agricultural production land, urban and rural living land area and degradation in grassland, and the occupation of ecological water land are the main reasons for the degradation of ecological environment in the basin, and the ecological environment improvement in the middle reaches is due to the transformation of a large number of other ecological land into forest ecological land.