The invention discloses a method for inverting a field flood runoff process in a data-free area, and relates to the technical field of hydrological data arrangement. The method comprises the steps ofadopting a natural watershed segmentation method; dividing a data-free area into independent sub-basins; simulating and calibrating a rainfall runoff process of a drainage basin above a downstream hydrological station in a data-free region; obtaining hydrological model parameters of a data-free area; constructing a hydrological model of a data-free area, and obtaining the runoff process of the flood data-free area by substituting equal-interval rainfall data of the field flood of the runoff process to be solved of the data-free area and calibrating final parameters of the data-free area modelinto the hydrological model of the data-free area. Therefore, with the adoption of the method provided by the invention, a higher precision runoff process of the field flood can be obtained through simple operation under the condition that few materials are mastered.