Landslide hazard is the most serious type of geological hazards in Lanzhou City. On the basis of the collected information, internal and external factors which lead to landslide are quantified in GIS, the authors get the relatively stationary landslide hazard potential risk assessment figure of Lanzhou city. By analyzing the relationship between rainfall and landslide hazard, the authors get the rainfall threshold expression. The system provides four rainfall models and two early-warning models, which achieves the diversification of models. Each model of early-warning system provides three, four and five limits of threshold for the final mapping selection. Through MapGIS k9 IMS secondary development platform, the system realizes Web publishing of real-time information of landslide hazards.