[Objective] Agropastoral ecotones serve as crucial ecological shields and key supply areas for agricultural and livestock products, revealing the dynamics and future changes of carbon storage (CS) in these areas hold both theoretical and practical significance for achieving regional “Dual Carbon” goals and optimizing territorial spatial planning. [Methods] Taking the Tabu agropastoral ecotone in Inner Mongolia as the study area, the carbon density values were modified yearly based on precipitation and temperature. Based on long time-series land use and land cover (LULC), climatic, and socio-economic data from 2000 to 2025, the spatiotemporal dynamics and driving mechanisms of CS were analyzed by integrating the framework of PLUS–InVEST–OPGD models, and its spatial patterns under multiple scenarios in 2030 were simulated. [Results] ① From 2000 to 2025, the multi-year average CS in the study area was 834.29×106, exhibiting a fluctuating increase (P＞0.05,Cv=0.13). Spatially, CS presented a stable gradient characterized by higher levels in the south and lower levels in the north. Moderate- and low-FVC grasslands and farmland contributed up to 82.8% of the regional CS. ② LULC(q=1.00) and the enhanced vegetation index (EVI, q=0.52) were the key factors driving CS dynamics, while the explanatory power of GDP and human footprint increased over time. Interactions among factors were predominantly characterized by bivariate enhancement. ③ Based on historical development trends, CS under inertial development, socio-economic development, and production-living-ecology coordinated development scenarios in 2030 increased by 101.52×106 t, 121.97×106 t and 152.91×106 t compared with the base year (2022). [Conclusion] Medium- and low-FVC grasslands and farmland are the primary carbon pools in the agropastoral ecotone. The spatial variance of regional CS results from the coupling of multi-dimensional factors, with the influence of human activities continuously strengthening. The production-living-ecology coordinated development scenario better satisfies the dual demands of maintaining ecological shield functions and ensuring the supply of agricultural and livestock products in agropastoral ecotones.