Abstract:A large number of seismic landslides have been induced by Wenchuan Earthquake, among which a universal seismic landslide type was fragmentation-sliding seismic landslide, with the unique sliding characteristics and complexity of power mechanism. In order to study the development characteristics of this kind of seismic landslide,Niujuan Ditch seismic landslide in Yingxiu of Wenchuan County was used as a typical example. Initially,the critical control factors of the formation for the fragmentation-sliding such as landforms, litho logy, slope structure, the role of seismic were studied. Then a detailed interpretation of the process of fragmentation sliding with four stages and 7 turning points of the direction—“slide to start collision fragments debris slide the accumulation of stagnant” were given.The application of the mechanism—“seismic start fragmentation accelerating” has an efficient explanation for why there are features of ultra-high-speed, slip away-way, large-scale for seismic landslide, which will be a typical and academic significance.