Abstract: From 12 to 14 of August 2010,heavy rain even rainstorms have been dropped in part of area in Sichuan province,and catastrophic debris flow have been induced in Qingping town of Mianzhu city,Yingxiu town of Wenchuan county and Longchi town of Dujiangyan city,which belonged to the worst-hit areas of the 5 12 Wenchuan earthquake.This disaster was referred by government as the 13 August 2010 catastrophic debris flow in Sichuan province.This debris flow disaster demonstrated that the debris flow in seismic zone or in none-seismic zone,pre-earthquake or post-earthquake had significant differences in distribution,forming condition,scale,moving style as well as other disaster mode and harmfulness.Firstly,a brief introduction to the 8 13 Qingping,Hongchungou of Yingxiu and Longchi debris flows have been made in this paper.The characteristic and formation reason of the 8 13 catastrophic debris flow,in Wenchuan earthquake region,have been analyzed and summarized and several revelations and suggestions to the prevention of the debris flow in disaster area have been put forward.The research result showed that the 8 13 debris flow not only had the characteristics of group properties,sudden features,destructiveness and hazard chain effect,but also had the significant characteristics of zonal distribution along the seismic fault,materials mainly coming from rock slide deposit which triggered by the Wenchuan earthquake and down-cutting being the mainly moving mode.Extraordinary abundant loose solid materials and local short-time heavy rainfall by the extreme climate in the earthquake region were the basic reason of the debris flow occurrence.In allusion to these new characteristics of the debris flow in Wenchuan earthquake region,the prevention measures to debris flow in earthquake region should be strengthened,especially those valleys of great debris flow hidden trouble.On the one hand,the standard of the garrison should be improved and the engineering management as well as specialty monitor should be intensified.On the other hand,risk management and control ideal should be brought in.The combination of prevention and administration,the combination of soft and hard,the combination of engineering measures and non-engineering measures,and the combination of administration and management was supposed to be focused on.What else,mobilizing the whole society to prevent geological disaster all together.