Land serves as a pivotal element connecting social-ecological systems; understanding the shifts in land ecosystem network characteristics and their associated ecological risks crucial for ensuring regional ecological security. However, existing studies assume that the system components are independent of each other and primarily focus on static risk assessment in the process of ecological risk assessment, ignoring the integrity of the system itself and the dynamic correlation between internal components. Here, using southwest China as a case study, we constructed a complex network of land ecosystems based on land use stock and flow, revealed the dynamic evolution of the regional land ecosystem network from 1990 to 2020, identified key transmission land types using local node parameters, established risk evaluation criteria for complex networks, simulated the risk propagation process under various stress conditions, identified the critical risk nodes and risk thresholds of land ecosystem network, and proposed sustainable land management strategies. Results indicated that:(1) The regional land ecosystem network experienced an "unstable-stable-unstable" evolution process during the study period; the average shortest path of the network was relatively short (1.22), while its network transitivity (0.88) and network density (0.74) were relatively high in 1990—1995, 1995—2000, and 2015—2020, revealing that frequent and complex interactions among various land type nodes caused the land ecosystem to be in a highly dynamic state, thereby resulting in the land ecosystem network"s weak stability during these periods. (2) Drylands, woodlands, shrubs, and high-coverage and medium-coverage grasslands are regional key transmission nodes, characterized by high integrated centrality, served as pivotal transfer hubs in the land ecosystem network of Southwest China, and their stability directly affects the structure and function of the system. Once disturbed, they will have a profound impact on the entire network, thus necessitating specific protection measures. (3) Drylands, woodlands, and shrubs were critical risk nodes leading to the imbalance of regional land ecosystem networks. When their maximum shrinkage area proportions reached 60%, 40%, and 60%, respectively, the cumulative effect of system risks would lead to network collapse, revealing that land use types with large stock and significant ecological functions play a pivotal role in the risk transmission process of regional land ecosystem networks. Their alterations can initiate cascading failure among system components, intensifying the system"s vulnerability. (4) Adopting agricultural water resource management and allocation, forest management and landscape configuration, as well as degraded grassland function optimization, can enhance the resilience of regional land ecosystem networks.