The flow-induced vibration response simulation of gate through model experiment and numerical model is an effective method to investigate the gate vibration problem. In this paper, the spillway under-port radial gate of a hydropower station was studied. A hydraulic model and a hydro-elastic model were designed according to the physical model experiment requirements. The hinge force measurement and the response of dynamic stress and displacement of flow-induced vibration of the gate were tested. The relationship between the hydraulic condition and the vibrations of pier and gate was analyzed. The test load was applied to the coupled gate-pier numerical model and the gate model in which the pier was treated as rigid constrain for dynamic analysis, respectively. The results showed that the pier vibration has insignificant impacts on dynamic stress and vertical dynamic displacement of the gate, but has significant impacts on the horizontal and lateral dynamic displacement of the gate. Finally, the dynamic safety of the gate was analyzed using the physical and numerical model.