The debris flow in Zhangmu gully is a great threat to Zhangmu treaty port

which is the only national level 1 treaty port in Tibet. In order to design a program to prevent debris flow

the study analyzed the forming conditions and dynamic characteristics of the debris flow gully

then evaluated the possibility of the occurrence of debris flow through quantitative and comprehensive method and fuzzy mathematic comprehensive evaluation method respectively. The result showed that Zhangmu gully is prone to has slight debris flow

but also has a possibility of moderate debris flow. In addition

monitoring results of the water flow showed that the running water in Zhangmu gully is the mainly supply source of groundwater in loose layer under Zhangmu town. This may has negative effect on the stability of Zhangmu landslide group.