Integrating ecosystem services into development assessments is crucial for sustainable urban and societal development. This requires a detailed examination of how land use change affects the spatial and temporal dynamics of ecological environmental quality (EEQ), considering regional variations. This study investigates the intricate relationship between land use change and EEQ by referring to the Territorial Impact Assessment (TIA) framework and introducing a novel concept of regional sensitivity. Focusing on Guangdong Province, China, from 2000 to 2020, the study analyzes the spatiotemporal evolution of EEQ at the county level in response to land use change. The findings show an initial decline in EEQ followed by a recovery, with an overall slight upward trend, evident in the Pearl River Delta and northern regions. The study also identifies areas encompassing nearly half the province's total area that experienced EEQ degradation during the study period. By applying the TIA framework with regional sensitivity indicators, this research not only contributes to improved EEQ change assessment methodologies but also informs the development of more regionally-specific sustainable land use and urban development policies. Ultimately, this study provides scientific support for navigating the challenges of achieving sustainable urban development in the face of evolving environmental conditions.