Abstract: The Gansu section of Yellow River Basin is an important ecological barrier in China. Clarifying the trends and driving mechanisms of ecological environment change is of great significance for promoting ecological protection and sustainable high-quality development in the Yellow River Basin. Based on Google Earth Engine (GEE), we used remote sensing data from 2000 to 2022 to construct the remote sensing ecological index (RSEI) model, and analyzed the spatiotemporal changes and driving mechanisms of ecological environment quality with Theil-Sen median trend analysis, Mann-Kendall test, coefficient of variation, Hurst index, and geographic detector. The results showed that the ecological environment quality of the Gansu section of Yellow River Basin exhibited an overall periodic fluctuation with an upward trend from 2000 to 2022. Spatially, there was a pattern of higher quality in the west than in the east and higher in the south than in the north. The ecological environment quality of the study area was mainly classified into good, moderate, and poor levels. The improved areas accounted for 87.5% of the total area, and the degraded areas accounted for 12.4%. Within the study area, 76.5% of the regions exhibited rela-tively high ecological stability, while 23.6% of the regions exhibited relatively low ecological stability. It was predicted that 64.2% of the regions might face the risk of ecological degradation in the future. Precipitation was the main factor affecting the ecological environment quality, and its interaction with factors such as altitude, temperature, and land cover significantly enhanced the explanatory power for ecological environment changes. This study could provide a scientific basis for monitoring and protecting the ecological environment quality in Gansu section of Yellow River Basin.

Key words: ecological environment quality; remote sensing ecological index (RSEI); Google Earth Engine (GEE); geographic detector; Yellow River Basin