Abstract: According to the characteristics of the regional floodwater utilization measures such as reservoirs,flood detention areas and canal storages and the risk generating mechanism of these floodwater utilization measures,the analysis method synthesizing risk rate and risk degree is used for computing the flood risk from the floodwater utilization of subregions and the various utilizing measures.Based on the relationship between the risk of the regional floodwater utilization and the risk from the floodwater utilizing measures of subregions,this paper proposes the mathematical model considering the fuzzy property of the flood risk assessment for evaluating the integrative risk of the floodwater utilization by using the fuzzy theory and the analytic hierarchy process,details with the hierarchical structure and the solution procedures of the model,the synthetic analysis technique of the risk rate and risk degree and the method for identifying the weights of fuzzy evaluation factors.Finally,taking the Beisanhe watershed in Haihe River Basin as example,the integrative risk rate is computed using the proposed model for evaluating risk in the regional floodwater utilization.