Abstract: Taking the landslides of Langao County as the object of study, R-factor analysis is used to analyze the influential factors of landslide development. The results are as follow. According to its degree of influence, the dominant factors which contribute to landslide development from great to small are respectively the distance from the slope forward to the river, human engineering activities, landform and structural plane. The secondary factors which contribute to landslide development from great to small are respectively the distance from the slope forward to the river, the excavation of slope toe, aspect of slope, dip of structural plane, topsoil(the percentage of slope area) and the detritus content of sliding mass. Combining the dominant terms and the secondary factors analysis, the main controlling factors, in turn, are the distance from the slope forward to the river, aspect of slope and dip of structural plane. This research provides not only a new analyzed method for landslide hazard, but also gives a new idea for prevention and mitigation landslide hazard.