Objective The western Sichuan province has an inherently fragile ecological baseline, with prominent issues of soil erosion and land desertification. There is an urgent need to clarify the spatial patterns of ecological vulnerability to support targeted conservation efforts.

Methods Based on national technical guidelines, a 3S technology-based evaluation system for soil erosion and land desertification vulnerability was constructed. Spatial analysis and integrated mapping were completed using multi-source remote sensing and ground data.

Results The overall ecological environment in the western Sichuan province was mainly classified as "vulnerable", with an area of 30 800 km², accounting for 90.96% of the total area of western Sichuan. Areas classified as "moderately vulnerable" and "extremely vulnerable" accounted for 8.94% and 0.10% of the total area, respectively. Among them, vulnerability to soil erosion was primarily at the "vulnerable" level, while land desertification vulnerability was mainly at the "moderately vulnerable" level, accounting for 95.86% and 90% of the total area of western Sichuan, respectively. In some areas of Batang county, Litang county, Kangding city, Jiulong county, as well as Gongga Mountain Nature Reserve and Hongba Nature Reserve, the ecological environment was extremely vulnerable, requiring strengthened ecological protection and maintenance.

Conclusions The findings of this study can provide a scientific basis for optimizing ecological protection red lines and implementing targeted management in vulnerable areas of western Sichuan.