Abstract: The gate of flood discharge tunnel in Wudongde Hydropower Station is an radial gate, which has the characteristics of large orifice size, high head, large flow velocity and partial opening operation. It is of great significance to study the dynamic characteristics of the gate under the flow-induced vibration. In this paper, the numerical model (FEM) and physical model were carried out to simulate and test the dynamic safety of the gate. The following conclusions were obtained: the natural vibration frequencies of the gate within 7th order obtained by the two models were relatively close, and the vibration modes were the same, which verified each other's reliability. The experimental stress results of the physical model were close to those numerical results. The dynamic and static superposition stress of the main members such as the gate support arm and the beam was not more than 157MPa, and the stress on the web plate at the joint of the lower support arm and the support hinge of the gate was large, but it did not exceed the local allowable stress value.