Flood probability forecasting method based on multi-source uncertainty

The invention relates to a flood probability forecasting method based on multi-source uncertainty. The method comprises the following steps: estimating surface rainfall probability distribution basedon an incomplete rainfall monitoring group; constructing a suboptimal solution set of each model parameter, and obtaining probability distribution of the model parameters; randomly generating a combination of surface rainfall and parameters, and driving the hydrological model to generate a plurality of groups of initial forecast flow processes; estimating the probability that each model is relatively optimal by using a BMA method; and randomly extracting the optimal model and the corresponding initial forecast flow, and estimating the posterior probability distribution of the forecast flow torealize probability forecast. According to the invention, uncertainty in three aspects of rainfall input, parameters and a model structure is comprehensively considered. A calculation method for realizing flood probability pre