Abstract: The emergency protection of the levee breach is based on hydraulic characteristics of water flow, and the closure methods directly affect the closure efficiency. First, the flood evolution process of the breach flow was simulated, and the water depth calculation results were compared with the experimental data given by C. Biscarini. The results agree well with the experimental data, which verifies the reliability and accuracy of the numerical model. Based on FLOW-3D software, a 3D numerical model for dike breach flow simulation of a river in Shangrao city was established, and the breach closure process was simulated respectively by the vertical closure method and the horizontal closure method. The water level and velocity field distribution law near the breach during closure process were obtained. The numerical results show that the water level obviously increases and the flow velocity increases in front of the block stone by the vertical closure method or the horizontal closure method, and the maximum velocity and water depth are distributed respectively in the left and right positions near the breach. According to the velocity distribution law near the breach, wrapped dike head measures should be taken on the left breach of dike toe, then the flow velocities may be reduced by costing large-size block stones, one by one and finally a group casting way would be taken for the closure. In this paper, the numerical model and simulation methods can provide a reference for dike emergency protection and dike breach closure.