Global warming significantly undermined the stability of ecosystems and their resilience to environmental disturbances. In this study, we adopted a method based on the Critical Slowing Down (CSD) theory to investigate the spatiotemporal dynamics of ecosystem resistance in the Beijing-Tianjin-Hebei region from 2001-2021. The monthly net primary productivity (NPP) series, derived from long-term MODIS gross primary productivity (GPP) products in conjunction with auxiliary datasets including leaf area index (LAI), meteorological variables, and other relevant biophysical parameters, served as the characterization variable of the ecosystem state, as it effectively reflects the photosynthetic capacity and overall health of vegetation. We quantified resistance by calculating the time autocorrelation (lag of 1 month) of the ecosystem state for each vegetation type. The changes in ecosystem resistance in the Beijing-Tianjin-Hebei region from 2001 to 2021 were analyzed. By integrating the abrupt change points of resistance, we identified the precipitation threshold required to maintain ecosystem stability under varying temperature conditions. The results indicated that: (1) The resistance of different vegetation ecosystems in the Beijing-Tianjin-Hebei region from 2001 to 2021, ranked from highest to lowest, was as follows: deciduous broad-leaved forest, deciduous coniferous forest, evergreen coniferous forest, shrubland, mixed forest, and grassland. (2) Approximately 96.1% of the forest and grassland areas exhibited an increasing trend in net primary productivity (NPP), indicating enhanced vegetation growth. However, about 73.4% of these areas showed a decline in ecosystem resistance, suggesting a potential vulnerability to environmental changes despite increased productivity. From 2014 to 2021, significant fluctuations in resistance were observed, with the highest peak occurring between March and June 2019. The regions experiencing abrupt changes were primarily concentrated at the junction of southwestern Beijing, northern Baoding, and southern Zhangjiakou. Notably, sudden increases in resistance were predominantly found in deciduous broad-leaved forests, while sudden decreases mainly occurred in mixed forests. (3) Based on the identified abrupt decline points in ecosystem resistance, the monthly precipitation thresholds necessary to maintain stability for deciduous broad-leaved forests, evergreen coniferous forests, mixed forests, and grasslands under different temperature conditions were determined. Taking the average monthly temperature of 14.1 ℃ during the dry season in the Beijing-Tianjin-Hebei region as a reference, the minimum monthly precipitation required to prevent adverse ecosystem changes was estimated to be 32.0 mm for evergreen coniferous forests, 24.0 mm for deciduous broad-leaved forests, 16.1 mm for mixed forests, and 27.9 mm for grasslands. These findings provide valuable insights for ecosystem management and conservation strategies in the context of global climate change.