Abstract: The trashrack attached to a high dam is subjected to earthquake and hydrodynamic exciting. The vibration induced by fluid-structure interaction affects trashrack life frequently due to amplification of vibration, resonance, flutter fatigue, and so on. In this paper the vibration response induced by the fluid-structure interaction of trashrack is studied and the relationship between the frequency of trashrack and the flow velocity is established. The efficiency of this method is shown by one working example .