Polongzangbu Basin, located in southeastern Tibet, is known by the world for its debris flow hazards, especially the debris flow, taking place in Zamulongba gully on 9th April, 2000, which blocked Yigong Lake 62 days and the following breaking flood cursed severely losses. Presently, the debris flow activities occur frequently. Based on the historical data, remote sensing conveying and field investigation, authors have determined that there are 104 debris flow gullies in Polongzangbu Basin, 87 of which have clear channel. The debris flow gullies locate the altitude between 2 500 m and 4 000 m, and their basin areas are between 0.8 km 2 and 185 km 2, especially 80 percent of which are between 1.0 km 2 and 30 km 2. According to the cause of formation, debris flow gullies in this area could be divided into 3 types: glacial, glacial lake burst and rainfall debris flow. At last, this paper discusses the impact of debris flow on the local economic development and environment.