Abstract: Massive seismic landslides are triggered by Wenchuan Earthquake, and rock mass of the landslides is generally caught with different degrees of seismic damage. Field investigations of Daguangbao landslide are conducted, and certain regularity is obtained that the damage degree of different rock mass parts relates with buried depth, topography and lithology conditions. The influencing factors for the damage degree of shattered landslide rock mass under high seismic action are investigated through fatigue tests from the viewpoint of dynamics. The test results indicate that the upper limit stress is the primary factor to influence the damage degree of rock mass, and the stress level is the premise of vibration frequency which influences the damage degree of rock mass. Further analysis is proceeded, and it is found that different sites of landslide are controlled by the differences of buried depth and topography, resulting in different seismic forces and stress states, and they are the dynamic factor for the damage degree of rock mass. The differences in the structure of rock mass with different lithologies will lead to different failure characteristics and determine different damage degrees under the same seismic load, and they should be treated as internal factors. The strong damage of rock mass induced by strong impact force of earthquakes at the initial outbreak in a short period and the defects of rock mass structure are the basis of the final rock seismic damage. The aforementioned researches provide a basis for the rapid qualitative evaluation of seismic damage of rock mass under strong earthquakes, and enrich the formation mechanism of the rock mass fragments in Daguangbao sliding zone.