Flood frequency calculation method and device under climate change situation

The invention provides a flood frequency calculation method and device under the climate change situation. The flood frequency calculation method comprises the steps that flood monitoring historical data of a target section of a river in a preset historical period is obtained, and climate change parameters in an estimated period is obtained; a non-stationary GEV model is determined according to the flood monitoring historical data; the climate change parameters are input into a distributed hydrological model to calculate the daily runoff volume of the target section of the river within the estimated period; and the flood frequency of the target section of the river in the estimated period is determined according to the non-stationary GEV model and daily runoff volume. In the embodiment ofthe invention, the accuracy of the flood frequency determined according to the non-stationary GEV model and daily runoff volume is relatively high, and thus the accuracy of the flood frequency in thesimulation estimated perio