Zhamo highway is located in the southwest Tibet, which has been suffering from frequent debris flows, landslides, avalanches, and floods in the last 50 years, because of its high relief (from 4300m alt at the Duorela Mountain pass down to 710m alt at the bank of Yaluzangbu River) and complex conditions of geomorphology and climate. As one of most frequent and serious disasters, debris flow is widely distributed and controlled by the vertical zonation. This study tries to explore the 8 vertical zones along the highway and their influences on debris flow on the basis of field investigation both on regions and individual gullies, combining with the indoor experiments and analysis. The goal is to reveal the formation mechanism of debris flow in different vertical zones and the hazardous process. Then we propose criterions for route selection and planning of engineering structures, so as to provide a scientific foundation for the construction of the highway.