As a critical ecological barrier in northern China, Inner Mongolia provides key ecosystem services (e.g., forage supply, soil retention, carbon sequestration) but faces ongoing risks such as land desertification, water scarcity, and biodiversity loss. This study analyzes spatiotemporal variations in ecological risk (ER) and ecosystem service value (ESV) from 2000 to 2020, revealing complex dynamics shaped by both natural processes and human interventions. The results demonstrate dramatic ESV fluctuations, with grassland values showing a V-shaped trajectory (-11.1 % during 2000-2010 followed by +11.7 % recovery), wetland values declining 5.8 % then recovering 4.1 %, and forest values initially increasing 9.1 % before decreasing 7.5%, resulting in an overall ESV decrease of 2.0% followed by a 1.9% rebound. Ecological risk patterns remained relatively stable, with mid-low risk dominating (56.45 % in 2000 to 56.19% in 2020) and high-risk zones consistently below 0.5 % coverage, though wetlands accounted for over 97% of these persistent high-risk areas. Analysis of service interactions revealed strong synergies between grain production and climate regulation (r = 0.96), trade-offs between provisioning and other regulating services (r = -0.10 to -0.06), and increasing synergies among all risks by 2020 (r = 0.28-1.00). These patterns emerged from competing drivers including rapid urbanization (39.6 % expansion of construction land), effective conservation policies driving grassland recovery, and climate variability. The findings highlight both the success of restoration measures in recovering grassland and wetland services and the ongoing challenges represented by persistent high-risk wetlands and declining forest values, underscoring the need for integrated strategies that combine targeted wetland protection, improved forest management, optimized grassland utilization, and careful balancing of cross-service trade-offs to ensure the sustainable development of this fragile yet vital ecosystem.