[Objectives] This study aims to elucidate the spatiotemporal variations and driving mechanisms of ecological environment quality in Dalian City, providing a scientific basis for regional ecological protection and high-quality development. [Methods] The Remote Sensing Ecological Index (RSEI) of Dalian City was constructed based on the Google Earth Engine (GEE) platform. The Sen’s slope and Mann–Kendall (Sen–MK) trend test were employed to analyze the spatiotemporal evolution of ecological environment quality from 2000 to 2023, while the Hurst exponent was applied to predict its short-term future trends. Furthermore, the optimal-parameter geographical detector was used to identify the major driving factors and their interactive effects. [Results] ①From 2000 to 2023, the ecological environment quality of Dalian exhibited a fluctuating yet overall improving trend, with significant spatial heterogeneity characterized by a “better in the north, poorer in the south; lower in urban areas, higher in suburban zones” pattern. ②The extent of ecological improvement during the historical period exceeded that of degradation, and the short-term trend is expected to continue improving. However, some local areas show risks of trend reversal, indicating the need for enhanced ecological restoration and management interventions. ③The single-factor detection results revealed that land-use type was the dominant factor affecting ecological environment quality, followed by elevation and slope, while the influence of socioeconomic factors has been steadily increasing over time. The interaction detection results indicated that the combination of land-use type and annual precipitation consistently represented the strongest driving force across different periods, revealing the compound effects of natural processes and human activities on ecological evolution. [Conclusions] From 2000 to 2023, the ecological environment quality of Dalian City has shown continuous improvement, with land use identified as the key driving factor. In the future, more attention should be paid to optimizing and maintaining ecological patterns in urban centers and coastal areas. Coordinated implementation of ecological protection and restoration projects alongside economic development is essential to promote the coordinated development of the regional economy and ecosystem, thereby supporting high-quality regional growth.