Many flood warning systems were developed for 2D environments and limited on specific flood hazard. With the purpose of overcoming these disadvantages, it is necessary to propose new methodologies and techniques for 3D real time flood simulation. In this paper, a novel flood hazard warning system has been proposed. It describes and defines the relationship between the different parts of the simulation system in order to offer not only numeric data or figures, but also more meaningful and appealing 3D visual information. Consequently, the performance of this simulation system depends on the quality of the three sub systems: 3D real world modelling system with GIS data, 3D environment reconstruction system and 3D flood simulation system. A new flooding model has been developed which can handle dynamic flood behaviour and predict inundation areas in real time. In order to validate our flood warning system, the region of Tewkesbury in England has been simulated with a potential flood. The flood spreading process is shown during different time and the detailed inundation area is presented for further disaster evaluation. The study achieved two main objectives: implementing a useful flood simulation with real world model and reconstructed environment for flood hazard warning; producing a friendly simulation system interface for either a decision maker or experienced user.