The Guanzhong-Tianshui Economic Zone (GTEZ), a vital land corridor for the Belt and Road Initiative (BRI), features a system structure of "Qinling Ecological Barrier-Urban Agglomeration-Loess Plateau Ecologically Sensitive Zone." This unique spatial configuration makes ecosystem health (EH) assessment particularly crucial. This study employs a comprehensive diagnostic methodology by systematically integrating the rigorously validated optimal CatBoost model into the Vigor-Organization-Elasticity-Services (V-O-E-S) framework, combined with SHAP analysis. Supported by SHAP uncertainty quantification, this approach systematically reveals the spatiotemporal evolution of EH and the dynamic changes of its driving factors in the GTEZ from 1990 to 2020. Key findings include: (1) EH dynamics followed a "deterioration-improvement" pattern; (2) Driving factors gradually shifted from socioeconomic to natural factors; (3) EH showed significant spatial clustering, with highvalue areas concentrated in the southern part of the study area, while low-value areas were predominantly distributed in the western and the central basin of the study area. This study validated two core hypotheses on the dynamics of EH and succession of EH driving factors in the GTEZ. The results provide a scientific basis for ecological management and spatial planning in the region and offer new insights into the synergistic interactions between human activities and natural processes under global environmental change.