The Yangtze River Basin has a wide range and complicated topography. In recent years, under the background of climate and land cover change, the ecological response of the whole ecological quality of the Yangtze River Basin is still unknown. To reveal the spatiotemporal changes in ecological quality in the Yangtze River Basin from 2001 to 2019 and their relationship with environmental and topographical factors, this study used the Google Earth Engine (GEE) platform to calculate the remote sensing ecological index (RSEI) based on the Moderate-resolution Imaging Spectroradiometer (MODIS) product image set, combined with the digital elevation data set and statistical yearbook. The data evaluated the ecological quality of the Yangtze River Basin and analyzed its causes. The results showed that: 1) the average RSEI of the Yangtze River Basin showed an overall upward trend, the growth rate was 0.027 (year⁻¹), and the variation ranged from 0.5 to 0.568. The overall ecological quality rank was mainly neutral and slightly good. 2) The ecological quality of 85.7% of the Yangtze River Basin remains stable. A total of 11.2% of the regional ecological quality is improving, and 3.1% of the regional ecological quality is declining. Areas with reduced ecological quality are concentrated in the Hengduan Mountains. The dominant LST factor drives the deterioration of its ecological quality at a rate of −1.06 (year⁻¹). The areas with improved ecological quality are concentrated in the upper and middle reaches of the Yangtze River. The dominant WET factor drives its ecological quality to improve at a rate of 0.27 (year⁻¹). 3) From the perspective of topography, the ecological quality of the Yangtze River basin shows a wave-like decline and first rises and then falls in elevation and slope (the elevation is bounded by 2000 m and 6000 m, and the slope is bounded by 15°.). The average RSEI of the Yangtze River Basin is the highest on the northwest slope (0.554), and the ecological quality of sunny slopes is generally higher than that of shady slopes. The research shows that from 2001 to 2019, the overall ecological quality of the Yangtze River Basin has improved and evolved, but the ecological quality of the Hengduan Mountains has declined. Therefore, implementing different ecological protection policies in different regions is an important strategy for enhancing the stability of the ecosystem.

长江流域幅员辽阔，地形复杂。近年来，在气候和土地覆盖变化的背景下，长江流域整体生态质量的生态响应尚不明朗。为揭示2001—2019年长江流域生态质量时空变化及其与环境和地形因素的关系，本研究利用谷歌地球引擎（GEE）平台计算基于中分辨率成像光谱仪 (MODIS) 产品图像集，结合数字高程数据集和统计年鉴。数据评价长江流域生态质量并分析其成因。结果表明：⁻¹ )，变化范围从 0.5 到 0.568。整体生态质量等级以中性为主，略好。2）长江流域85.7%的生态质量保持稳定。共有11.2%的区域生态质量在改善，3.1%的区域生态质量在下降。生态质量下降的地区集中在横断山区。占主导地位的 LST 因素以 -1.06（年^{-1 年}）的速度推动其生态质量的恶化。生态质量改善的地区集中在长江中上游地区。主导湿因子驱动其生态质量以0.27（年^-1）。3）从地形看，长江流域生态质量呈波浪状下降，高程和坡度先升后降（高程以2000m和6000m为界，坡度为15°。）。长江流域西北坡平均RSEI最高（0.554），阳坡生态质量普遍高于阴坡。研究表明，2001年至2019年，长江流域整体生态质量有所改善和演变，但横断山脉生态质量有所下降。因此，在不同地区实施不同的生态保护政策是增强生态系统稳定性的重要策略。