Abstract: This study focuses on Yunnan Province, where the MSPA model is applied to identify ecological core areas. An ecological sensitivity analysis is then conducted by integrating indicators such as desertification level, slope, Remote Sensing Ecological Index, Normalized Vegetation Index, and land-use type to ultimately determine ecological sources. Based on this, a fundamental ecological resistance surface is developed and refined using the Remote Sensing Ecological Index to derive a comprehensive resistance surface. Finally, the circuit-theory model is employed to construct ecological security patterns for 2000, 2010, and 2020 by integrating ecological sources and the comprehensive resistance surface, and to examine their spatiotemporal dynamics. The results showed that the total area of ecological sources of Yunnan Province in the three periods was 74781.19 km², 61296.27 km², and 75867.32 km², respectively. The distribution pattern of ecological sources revealed an aggregation in the west and a scattered distribution in the east. The ecological resistance value is high in the northeast and low in the southwest, and it decreases annually. The number of corridors increases, the length decreases initially and then increases, and the spatial distribution is more pronounced in the west and less pronounced in the east. The number and area of pinch points increased initially, then declined, indicating an overall upward trend. The obstacle points showed a consistent decrease, with pinch points concentrated in low-resistance areas in the west and obstacle points densely distributed in high-resistance regions in the east. Overall, the ecological security pattern in Yunnan Province exhibits significant spatial heterogeneity, with the southwestern region requiring prioritized ecological protection and the northeastern region needing focused ecological restoration. This study examines the spatial and temporal evolution of the ecological security pattern in Yunnan Province. It proposes ecological protection and restoration measures, providing a scientific foundation for the subsequent realization of balanced economic and ecological development.