Within the isothermal zone, NPP tends to increase with increasing precipitation levels [30; 31]. Nevertheless, this conspicuous pattern evidently does not align with the focus of our study; our objective is to investigate the impact of urban expansion on vegetation while controlling for other factors, especially precipitation. While the NDVI, EVI, and NPP indices can reflect vegetation conditions [32; 33], there are still general challenges when these indicators are used to assess the impact of urban expansion on arid land vegetation [34; 35]. First, arid land vegetation is significantly influenced not only by urban expansion but also by precipitation, a crucial factor that the aforementioned indicators often neglect [36; 37]; consequently, these methods may not accurately and quantitatively reflect the actual impact of urban expansion on arid land vegetation. Second, the majority of current studies predominantly focus on the adverse effects of urban expansion on vegetation [38]. Nevertheless, urban expansion can also positively impact vegetation through various measures, such as increasing urban green spaces. Hence, there is a pressing need for a more objective assessment metric to quantitatively determine the positive and negative effects of urban expansion on vegetation in arid regions [39; 40]. The Vegetation Disturbance Index (VDI) represents a novel approach for quantitatively assessing the impact of urban expansion on arid land vegetation. Compared with traditional vegetation indices, the VDI offers greater adaptability to changes in precipitation levels. By incorporating precipitation factors, the VDI diminishes the influence of precipitation fluctuations on vegetation, thereby providing a more accurate reflection of the actual impact of urban expansion on vegetation, particularly highlighting its effects. Moreover, the VDI enables a more precise quantitative assessment of both positive and negative impacts on vegetation. While capitalizing on the advantages of vegetation indices, the introduction of the VDI enhances the understanding of the tangible effects of urban expansion on vegetation and provides a more accurate and comprehensive tool for analyzing spatial distribution changes in vegetation [41; 42]. This facilitates a more comprehensive examination and response to the complexities of vegetation changes within the urbanization process [43; 44; 45]. This study aimed to reveal the dynamics of urban expansion and their impacts on the vegetation of the Lanxi urban cluster over the past two decades. Specifically, this research commenced by collecting land cover data spanning from 2001 to 2021, followed by meticulous preprocessing of the dataset. An examination of alterations in urbanized areas revealed the intricate dynamics of urban expansion over the course of approximately two decades. We subsequently amassed nearly two decades of Enhanced Vegetation Index (EVI) and precipitation data, subjecting them to rigorous preprocessing procedures encompassing cloud removal, interpolation, and resampling to ensure homogenous resolution. We performed overlay calculations on the data to obtain pixel-level VDI values. This facilitated a quantitative analysis of the holistic impact of urban expansion on vegetation within the Lanxi urban cluster throughout the 20-year timeframe. This research provides a comprehensive depiction of vegetation changes during the urbanization process in the Lanxi urban cluster. The findings of this research can serve as valuable references and guidance for future sustainable urban planning and ecological conservation in the region.