In this paper，the results of the flow-3d calculation for an example of dam break with rectangular obstruction were compared to the results of FLUENT and Wang，and the results were almost identical.The feasibility of Flow-3D software for three-dimensional numerical simulation of embankment burst is verified.Based on the simplified modeling of an actual river embankment，the three-dimensional numerical simulation of the embankment of different water heads and different flow conditions of the upstream water head and different flow conditions is established.The results show that the distribution of the velocity plane distribution in the upstream of the outlet is mainly distributed on the left side of the outlet.Therefore，we should pay attention to advance the mouth of the upstream side of the head handle，to prevent the dyke broaden by excessive velocity during the process of dyke breach closure.It can according to the velocity distribution of the outlet to corresponding sealing particle size when to select the sealing material.