Goupitan Double Curvature Thin Arch Dam is 232.5 m in height with an energy dissipation in plunge pool. Flood is maily discharged from top openings and middle outlets.The max. amount of discharge and the discharge power place the first in arch dams of the world, so the effect of the flow-induced vibration on the safety of the dam must be carried out.In this paper, a hydroelastic model with a scale 1∶150 is used in combination with FEM to study the flow-induced vibration problem of the dam. The results show as follows: The former four frequencies and their vibration modes got from two methods are quiet agreeable. The dynamic displacements and stresses are small in all test conditions, and would not harm the safety of the dam, but some local fatigue failure could take place after a long time vibration. The main stimulative forces are the dynamic pressures on the top openings and middle outlets of the dam. The flow-induced vibration of the dam is reduced through optimizing the shapes of the top openings of the dam.