Abstract: Road construction and operation, as a typical form of large-scale human activity, have become a strong disturbance to natural ecosystems. A rigorous understanding of road impacts on plant communities and their habitats, particularly how vegetation and soil vary with road age and distance to the road, together with the associated extinction risk of narrow-ranged species within the road-affected zone, is essential for evidence-based biodiversity conservation and ecological restoration along road corridors. Here, we investigated a major infrastructure project in the Sino-Nepal transport corridor on the Qinghai-Tibet Plateau, the China-Nepal Highway (~1,000 km). Using field vegetation and soil data collected from the road-induced indirect disturbance zone (10-150m from the road edge) on both sides of the highway, including 9 herbaceous sites and 19 shrub sites, we evaluated road effects at both community and species levels. Linear mixed-effects models (LMMs) were used to assess how road age and distance influence vegetation community attributes and soil physicochemical properties. Redundancy analysis (RDA) and Mantel tests were applied to examine relationships between community characteristics and soil properties in herbaceous and shrub communities. In addition, MaxEnt models were used to predict the potential suitable habitats and extinction risks of four narrow-ranged species within a 5-km buffer along the corridor. Results indicate that the 10-150m indirect disturbance zone is a key area of road-related ecosystem change. Roads act primarily through disturbance-driven changes in soil physicochemical conditions, which in turn shape plant community characteristics. Changes in herbaceous community composition and diversity were mainly driven by soil moisture content (SMC) and pH, whereas shrub communities were influenced by SMC, pH, total nitrogen (STN), total phosphorus (STP), and soil organic carbon (SOC), with effect magnitudes varying with distance to the road. Within the 5-km buffer, the highest predicted extinction risk was found for Taxus wallichiana (Tibetan yew), followed by Rhodiola himalensis and Rhodiola crenulata, while Meconopsis horridula showed the lowest risk. These findings advance understanding of how road projects affect ecosystems on the Qinghai-Tibet Plateau and provide practical implications for restoring road-affected ecosystems and conserving narrow-ranged species.