Abstract: Based on the pilot application of four function of forecast, early warning, drill and emergency plan (FEDE) for flood management, several core digital twin technologies supporting four functions of FEDE for flood management are studied, and some digital twin applications are summarized, which can provide reference for the construction of related digital twin applications. Driven by the actual demand of flood management application, the digital twin technology framework for flood management with four functions of FEDE is studied. Taking the main characteristics of digital twin "virtual and real mapping" as the main line, the core digital twin technologies such as digital river basins simulation system, digital scene and "twin" state synchronization supporting "virtual and real mapping" are studied. At the same time, several kinds of digital twin technology applications such as virtual monitoring, water project inspection, remote control and intelligent decision-making are summarized. It is concluded that digital twin technology has good merits in the application for flood management with four functions of FEDE, and also has feasibility in technology, which is worth further research and development.