On July 5

2004

a large-scale landslide-debris flow disaster took place in Dehong

Yunnan province

China.The disaster is located in the area Southeast of Qinghai-Tibet Plateau

the most severe region of geological hazards in China.More than 90 percent villages and towns are affected by the disaster in Dehong.18 people were killed and 24 people were missing.The total losses amounts to RMB 480 million.The disaster has four features:（1） the occurrence of disaster was catenulate;（2） the occurrence of disaster was in a cluster;（3） There were many trunks and branches of trees mixed with the debris flows;（4） the occurrence of debris flows was in low frequent.By analysing the characteristic of the disaster and disaster area

we can see that abundant loose solid materials

big landform elevation difference and the intensity rainfall process are the main reasons for the disaster.GIS and Landsat ETM+ are used to analyze the cause of disaster.The main cause of the occurrence is the especially heavy rainstorm.But Dehong′s severe weathered earth surface and fragmental terrain are essential conditions.Under those circumstances

disasters will be more and more active in the near future.To cope with this situation

closer investigation and risk assessment for Dehong must be executed.What should be done in next step is put forward.