To effectively avoid and/or mitigate the disasters caused by the slope landslide induced by rainfall, the information in association with the precise tendency evaluation and real-time pre-warning on the landslide becomes an urgent task to be accomplished. The tendency evaluation can be used as the basis for the selection of safety site and the planning and design of the slope stabilization measures. The pre-warning information can be used to predict the timing of landslide occurrence providing one to set up the rescue and evacuation plan. At the current stage, the aforementioned tasks are carried out on the basis of the in-situ monitoring and historical data in addition to the practical engineering assessment. However, by following the dramatically rapid growth of the establishment of digital elevation data bank and the technology of quantitative precipitation forecasting, in lieu of the dynamic numerical model to examine the landslide mechanism and to grasp the real-time tendency has become a mature methodology. The purpose of this study is going to analyze the slope landslide mechanism induced by rainfall by using both of 1-D and 2-D physical-based slope stability numerical models. The effects of various triggering hydrological conditions on the slope with various combinations of physiographical and geological conditions will be thoroughly examined. The Arc-Hydro topological module will also be used to effectively cope with the judgment of landslide region for the real case.