Experiments on flow induced vibration of a rectangular flat plate with two ends fixed in a confined channel are conducted in this study, and vibration response characteristics of the plate are obtained. The results show that the main physical mechanisms of vibration are turbulent-induced vibration and vortexinduced vibration. The turbulence excites response of the first natural frequency of plate and is amplified with the increasing flow velocity. The frequency of vortex-induced vibration shows a linear increase with the flow velocity, and the St number is 0.24 within the test range. The ‘lock-in’ phenomenon and resonance occur when the vortex shedding frequency is approaching the natural frequency, and the non-linear harmonic shows up. In addition, the wet modal analysis based on acoustic-solid coupling method were conducted and the predicted results show a good agreement with the experimental values.