The excessive exploitation of mineral resources adversely affects the regional ecological environment. Therefore, the timely assessment of changes in ecological environmental quality is crucial for the sustainable development and planning of coal resource-based cities. This study aims to explore an evaluation method for monitoring ecological environmental quality in coal resource-based cities. Specifically, we first built a comprehensive remote sensing ecological index (RSEI) based on four ecological indicators extracted from Landsat images in Zoucheng City. Subsequently, we combined the land use/land cover (LULC) data yielded from Landsat satellite images using the random forest algorithm with the time series RSEI data to analyze the spatiotemporal change characteristics of the ecological environment in Zoucheng City. The findings are summarized as follows: The mean values of the RSEI for the four periods (2006, 2011, 2016, and 2022) in Zoucheng City were 0.4501, 0.4562, 0.6417, and 0.5822, respectively. The mean RSEI increased by 40.66% from 2011 to 2016, demonstrating a significant improvement in the ecological environment. However, the mean RSEI decreased by 9.27% from 2016 to 2022 in Zoucheng City, indicating a decline in ecological environmental quality. This study can serve as a reference for understanding the ecological environment of other coal resourcebased cities.