Abstract: Debris flow disasters present major challenges for the design, construction, and operation of road networks in mountainous regions. This study focuses on a highway in the southern mountainous area of Xinjiang, China, where comprehensive field investigations were conducted to analyze the disaster-prone environment and developmental characteristics of debris flows along the route. Specifically, for the K180 highway section, debris flow dynamics were simulated using the FLO-2D numerical model under three rainfall scenarios (P=1%, 2%, and 5%) to assess key movement characteristics such as deposition depth and flow velocity. The results indicate that the region's geological structure, topography, weathering conditions, and rainfall patterns collectively create an environment prone to frequent debris flows. The relative error between debris flow discharge volumes calculated from empirical formulas and those derived from numerical simulations ranges from 8.52% to 13.98%, which falls within an acceptable margin and confirms the reliability of the simulation results. Under the P=1% rainfall scenario, certain roadbed sections of the original alignment are at risk of inundation. In contrast, the optimized route effectively avoids high-risk areas, reducing threats to road infrastructure. This study proposes a hazard assessment method based on debris flow dynamics, providing valuable guidance for highway design and offering a scientific basis for debris flow disaster prevention and mitigation in mountainous areas. This approach holds significant theoretical and practical value for research and engineering applications.