Aiming at the vibration problem of the gate body during hydrodynamic closing of the diversion tunnel in Batang Hydropower Station, a physical model with a scale of 1∶25 was established according to the criteria of hydro-elasticity and gravity similarity. The vibration acceleration, holding force and strain of the plain gate in the closing phase were measured in the model test. The results show that the maximum horizontal single-fold displacement amplitude is 91.974 μm, with which the gate vibration is unlikely to happen. The maximum Mises value of the structure is 11.32 MPa, the overall stress of the gate meets the strength requirements, and the plain gate is safe and reliable. Then a modal analysis of the plain gate was carried out using ANSYS Workbench. The analysis results show that the dry mode fundamental frequency is 40.05 Hz, the wet mode fundamental frequency is 35.40 Hz, and the main pulsation frequency is within 10 Hz when the gate is retaining water, which is significantly different from the wet mode order 1 frequency, so the possibility of gate resonance is low. The hydrodynamic model test adopted in this paper is suitable for the simulation of the dynamic characteristics of plain gates, it can predict and analyze the gate response to flow-induced vibration accurately. This research can provide some reference for the structural optimization design and operation safety monitoring of plain gates in similar projects.