Abstract: Based on Landsat 8 remote sensing imagery, Digital Elevation Model (DEM), and Integrated Forest Resources Map data from 2016 to 2020, this study constructed the Remote Sensing Ecological Index (RSEI). Combining Principal Component Analysis and regression modeling, we quantitatively assessed the spatiotemporal dynamics of eco-environmental quality and its driving mechanisms. The results indicate that the RSEI exhibited a trend of increasing initially and then decreasing, peaking at 0.711 in 2018 before declining to 0.697 in 2020, with an overall increase of 1.2%. Eco-environmental quality grades were predominantly "Excellent" and "Good" (annual average proportion: 71%). However, the area proportion of "Poor" and "Very Poor" grades increased from 11.5% to 13.1%, indicating significant degradation risks. Changes in eco-environmental quality were concentrated in areas with slopes of 5°～30° and elevations of 500～1000 m. Degraded areas were significantly more extensive on south-facing slopes than on north-facing slopes. Expansion of construction land and a regional drying-warming climate trend were identified as the primary negative driving factors, while vegetation coverage and humidity acted as positive regulators.. This study concludes that Taishun County exhibits a pattern of "overall stability with localized degradation" in eco-environmental quality. To address this, enhanced management of construction land and implementation of ecological restoration projects are recommended, with particular focus on south-facing slopes and high-elevation areas.