Abstract: Danbobei gully is the main tributary of Ya-lung River and is at the right bank of the river middle reaches.The gully occurred many debris flowsin the past.This paper analyzes the dynamic characteristics of debris flows in Danbobei gully.It summarizes the formation conditions of the debris flows.It confirms that the debris flows in Danbobei gully are gully rainfall type with low-frequency and high viscous debris flows.It analyzes the debris flow characteristics of the movement such as the flow velocity,the discharge,punching power and the transporting quantity.The debris flows may cause the Ya-lung River mainstream to the left shift.The construction of hydropower station and safety operation influence have realistic meanings.According to the characteristics of development activity of the debris flows and theirformation reasons,it is also suggested that building barricade wall at the left bank of the early construction site and the upper reaches materials site.The wall should occupy fewer flood channel cross sections for preventing blocking the river.