For the flow-induced vibration problem of the large-scale plate valve of a ship lock, we employ the method of mode test and FEM simulation to study the self-vibration characteristics of the plate valve. The result is applied to conduct the dynamic optimization design of the structure. The hydro-elastic model test is conducted to study the flow-induced vibration characteristics of the valve. It is found that the test value and the calculation value of the self-vibration frequency and the mode shape of the valve are consistent. The basic frequency is improved obviously, which avoids the high-energy region of the flow pulsation. The flow-induced vibration response is relatively small and will not induce harms.