The development of rural human settlement environments in ecologically sensitive areas, particularly the upper reaches of the Lancang River within the Sanjiangyuan region, has garnered significant attention due to its paramount importance in balancing economic growth and ecological conservation. However, the comprehension of sustainable development strategies within the confines of ecological carrying capacity in these regions remains inadequate. The present study aims to investigate the rural human settlement environment in Nangqen County, situated within the Sanjiangyuan region, and to explore adaptive construction strategies that facilitate harmonious coexistence between human settlements and the natural environment. Utilizing an ecological footprint model integrated with the ArcGIS platform, this research evaluates the ecological carrying capacity and its variations from 2000 to 2020. The results indicate that, despite the land ecological environment being generally safe, the total ecological footprint has surpassed a twofold increase, primarily driven by the expansion of animal husbandry activities. Furthermore, the study conducts a suitability assessment of rural settlements in Nangqen County, pinpointing areas that are most conducive to sustainable development and those that necessitate protection.