Based on the physical experiments, this study simulated the tsunami generation and propagation of tsunamis, collision with the drift and the impact of drift and buildings on land through the ALE finite element method in three-dimensional numerical wave tank .The run-up tsunami level, acting force with the drift and the velocity of drift was measured. Compared numerical computation data with the physical experiments, it verified the feasibility of ALE fluid-structure interaction method in the study on the behavior of drift by run-up tsunami. Based on this, analyzed the force that drift on building by run-up tsunami. The results show that the velocity of collision and the weight of the drift play a key role in the force that drift on building, however, the stiffness of building on land almost has no influence on it.