According to the relationship model between meteorological-geological disasters and prophase and antecedent precipitation,the fuzzy possibility of hazard grades for meteorological-geological disasters(MGD) is described.The PP (Perfect Prediction) principles and the certainty-factor method in ES(expert systems) are used to carry out the uncertainty-inference of MGD prediction,in order to establish the ES predicting model of meteorological-geological disasters.The model has been proved satisfactory in the flood season of 2004,predicted all the major meteorological geological disasters.The results indicate that it is feasible and effective to establish prediction model by dividing the precipitation(prediction factor) into two(actual and predicted) according to the PP principles and by using the expert-system predicting method for such low probability events as meteorological geological disasters.