The invention discloses a device and method for monitoring and early warning of flood damages based on multi-resource integration. The device comprises a hydrological actual state module, a flow forecast module, a weather forecast module, a radar analysis module, a forecast integration module and a module for product display and early warning release. The method comprises the steps that (1) the hydrological actual state module reads and monitors monitoring point data; (2) the weather forecast module reads input data and parameters to carry out weather mode forecasting; (3) the flow forecast module carries out flow forecasting according to the weather mode forecast and the monitoring point data provided by the hydrological actual state module; (4) the radar analysis module reaches basic data of a radar and estimates precipitation and optical-flow extrapolation; (5) the forecast integration module integrates and outputs information of the flow forecast module and the radar analysis module; and (6) the module for the production display and the early warning release completes the product display and the early warning release. The device and the method consider accuracy of radar extrapolation forecasting in forecasting of the position of a precipitation system and also consider capacity of numerical mode forecasting, so that limitations of the single method are avoided.