The invention discloses a flood early warning comprehensive dynamic index determination method, which comprises the following steps: collecting target index data, and normalizing each index value; calculating a subjective
weight value and an objective
weight value of each index data according to a subjective and objective combined weight method; the subjective
weight value and the objective weight value are combined to calculate the consistency coefficient of subjective and objective weights, a long-term low-
correlation index replacement mechanism is established, and then the weights are dynamically adjusted; determining a comprehensive dynamic index in combination with the corresponding index normalization data; risk grades are divided according to the
numerical range of the comprehensive dynamic indexes, and a judgment basis is provided for decision makers. According to the method, various flood
related factors are comprehensively considered, index weight values at different moments are calculated, a systematic early warning index determination method is constructed, the limitation of a traditional method is effectively overcome, flexible
adaptation can be achieved according to real-
time data and flood scenes, more accurate and more adaptive technical means are provided for flood early warning, and disaster prevention and reduction work is assisted.