The comparative analysis of the relative economic value curve of EPS probability and deterministic forecasts of the ensemble forecasting system shows that the probability forecasting system is obviously super.

On the basis of reviewing of the hydrological model, flood forecasting system and hydrologic forecasting uncertainty in home and in abroad, the parameter calibration techniques for conceptual hydrological model and the probabilistic hydrologic forecasting system were studied and discussed in detail.

In collaboration with the artificial neural network (ANN) scheme,a qualitative forecast model for the annual frequency of tropical cyclones and summer (June to August) rainfall affecting Guangxi was worked out.