Abstract：The landslides occur frequently in China. In particular，large-scale landslides are dominant and extremely important. In West China，the large-scale landslides are notable for their scale，complex formation mechanism and serious destruction，which are typical and representative in the world. Data were collected from some typical large-scale landslides occurred in mainland of China since the 20th century. Among these cases，nine landslides were comprehensively analyzed and discussed. These cases represent different geological conditions，different triggering mechanisms and induced factors. This study shows that the fundamental cause for large-scale landslide in China is due to the topographical and geomorphological conditions. About 80 percent of large-scale landslides were found in the first slope-descending zone of the mainland topography around the eastern margin of Tibet plateau. Moreover，this area is the most active area of the plate tectonic activities. The intensive interactions between the endogenic and epigenetic geological process cause serious dynamic change of the high steep slope，which are resulted in the development of large-scale landslides. Strong earthquake，extreme weather conditions and the global climatic change are the main triggering factors of large-scale landslides. In South China，it is easy to trigger large-scale landslides when storm causes 200–300 mm/d of heavy rainfall. In Northwest China，the thawing of the frozen layer in spring is the main cause of large-scale landslides in loess region. In recent years，global warming causes the temperature to rise，snow line to shift，glacier recession and glacier lakes to collapse. These factors are also the triggering factors of large-scale landslides in some areas. In addition，the causation of more than 70 percent of large-scale landslides is closely related to the human activities. Detailed analyses of the cases show that the mechanisms of large-scale landslides in China are complex. The large-scale landslides can be summarized into three types：rock landslides，soil landslides and landslides in debris. The typical geomechanical models of large-scale landslides in rocks are shown as following：the “three sections” model(i.e. sliding-tension cracking-shearing)，“retaining wall collapse”model，“horizontal-pushing”model in horizontal strata，large-scale toppling model in anti-dip strata，and the creep-bending-shearing model，etc.. Each model corresponds to some specific rock structure conditions and deformation processes. When large-scale rock landslides occur，they are generally accompanied by the suddenly brittle failure of the“locked section”along the potential sliding surface. The“locked section”is extremely important to the deformation control and stability of the rock slope，which is also the key factor for the assessment of slope geohazard and for the development of control methods. It is shown in engineering practice that the correct understanding and using of geological and mechanical model are the fundamental keys for the prevention of large-scale landslides.
