From the point of view of system theory, the landslide hazard system includes two subsystems: subsystem of hazard and subsystem of stricken. The consequence of landslide hazard is based on the interaction of these two subsystems. previous studies concenerate on evaluation of landslide stability. Hence, the study of a typical element at landslide risk is focused. And a method to calculate failure probability of typical element (frame structure) at landslide risk is discussed. Furthermore, the influences of both impact force and impact resistancecapability of element at risk on failure probability are analyzed, which shows that, for each elements at risk, the landslide impact area can be divided into absolutely dangerous zone, relatively dangerous zone and absolutely safety zone. In addition, with the condition that the structure failure probability is above 50%, as the variability of impact force increases, the structure failure probability decreases; with the condition that structure failure probability is below 50%, as the variability of impact force increases, the structure failure probability also increases.