The core islands of the Sichuan River section serve as a crucial component in implementing the strategy for ecological protection and high-quality development of the Yangtze River Basin. As a relatively independent geospatial unit, it has established a system for island settlement environments that integrates “mountain - water - forest - field - dwelling". However, geographic conditions, resource limitations, policy environments, and social changes are driving a significant transformation in the protection and utilization of these islands. By examining the spatial patterns of settlements, we classify the spatial types of island settlements and analyze the spatial organization of settlements on the river core islands in the Sichuan River section. This includes investigating the spatial characteristics of geographically related settlements, the relationship between the road network and settlement distribution, and the land use structure of mountains, water, forests, fields, and dwellings. This analysis enables us to summarize the dynamic adaptive relationship between “suitable cultivation land and residence” for constructing the island human settlement space. It offers insights into a small-scale, cluster-type, multi-nostalgia “architecture - environment - nature” organizational model for low-impact development of the islands, in line with the policy requirement of “no major development and major protection".