[Objective] To acquire the characteristics of debris flow in alpine mountain in order to analyze the mechanism and the harm degree. [Methods] Based on the field investigation, the "three high" distribution of debris flow (cold, high-altitude, high-intensity) along Sino-Pakistan highway, the inducing mechanism were researched. [Results] At this area, tectonic movement was active, rock mass structure was broken, joint fracture was developed, besides located in the alpine mountains, and affected by climate and the rock thaw to spall, thus created conditions for the outbreak of the debris flows. In addition, because of the unique structural characteristics of Tianshan Mountain, there were several hundred meters thick of sand and gravel layer to ensure the replenishment rate. High and steep terrain provided sufficient movement potential. Thereby concentrating rainfall and snowmelt role were the direct causes of the outbreak of debris flow. Erosion, collapse blocked and outburst came into being debris flow. [Conclusion] The debris flow in alpine mountain was mainly affected by climate, terrain, hydraulic power and geological conditions. With the greater difference from rainfall debris flow, it has obvious plateau characteristics, reflected in the source material, water and terrain conditions.