Abstract: As a "Water Conservation Functional Zone and Ecological Environment Support Area for the Capital", the ecological security of Bashang region in Zhangjiakou is crucial for Beijing-Tianjin-Hebei area. However, the region's fragile ecological environment faces significant challenges from environmental geological issues. This study comprehensively employed methods such as field surveys, remote sensing interpretation and GIS spatial analysis to reveal the evolution characteristics of the regional water-soil-vegetation environment between 1993 and 2020, and to evaluate the geological environmental carrying capacity. The results indicated significant pressure on the water resource system, manifested as a continuous decline in groundwater levels, reduce in spring discharge, river drying and shrinkage of lakes and ponds. The ecological environment presents a complex trend of "coexistence of local improvement and overall fragility", and land desertification has been effectively controlled, whereas soil salinization fluctuates. Based on these findings, a dual evaluation index system comprising of 10 factors for both the carrying background and carrying status was adopted. The comprehensive assessment revealed significant spatial heterogeneity in the region's geological environmental carrying capacity. 46.75% of the area was at a moderate carrying capacity level, while over 40% exhibited weak or very weak carrying capacity. These vulnerable areas were primarily distributed around the northern and western lakes and low-lying regions, which were high-risk areas characterized by the superposition of groundwater overexploitation and ecological degradation. This study could provide scientific basis for ecological protection and restoration as well as territorial space planning in the Bashang region, and holds significant practical importance for ensuring the construction goals of the "Capital Two Zones".