As one of the provinces with the highest economic growth, Zhejiang Province is experiencing geological disasters, such as landslides, mainly in the period June-September during tropical storms. Landslide hazard has been mapped considering a combination of environmental and triggering factors, then it has been classified in 4 hazard levels. For rainfall thresholds definition, an “effective rainfall” has been defined as the sum of the antecedent rainfall of the past days multiplied by a coefficient for typhoon and non-typhoon regions. Combining these thresholds with landslide hazard maps, a predictive model for landslide occurrences with 4 levels of warning was established in the Zhejiang Province. Rainfall monitoring and forecast provide data for evaluating the “effective rainfall” map, that is jointly used with the landslide hazard map to define the level of warning. According to the results, the government releases warning messages on Internet (Yin et al. 2007, Zhang et al., 2011). The system is webGIS based and is operational since 2004.