Abstract: The hydraulic characteristics of flow caused by the levee breach are very important for working out the schemes for closure of breach when there is a sudden levee breach due to breaking. A 3D numerical model is established to simulate the sudden levee breach flow based on the FLOW-3D software, by which, first, the 3D numerical simulation of distribution of the water level field induced by local instantaneous breaking flow has been carried out. And it is found that the calculated results based on FLOW-3D software have a good agreement with the representative research results given by C. Biscarini, which has verified the reliability and accuracy of the numerical model in this paper. Taking the levee located on a river basin as an example, a 3D numerical model is set up for the levee breakdown water flow outflowing from different levee breach ( including U-shaped, V-shaped, T1 and T2-shaped breaches). At the same time, and the distribution characteristics of the water level and velocity field near the breach in the case of these four breach shapes were calculated and analyzed. The simulated and analyzed results show that there was a rapidly lateral contraction and longitudinal fall of the water flow after inflowing into the breach, and the water depth and velocity lines at the breach appear to be approximate arched profile, which being small on both sides and large in the middle along the vertical water flow cross-section direction. And the maximum water flow velocities close to the levee breach occurred at the left toe. The numerical model and the simulation methods based on FLOW-3D software presented by this paper can provide a technical reference for working out the best schemes for the emergency closure of breach.