Abstract: A fixed square rigid body is submerged in water flowing, a thin elastic plate is attached to the rigid body in the centre of the downstream face. The vortices, which separate from the corners of the rigid body, generate periodic lift forces which excite continuous vibrations of the thin elastic plate. Numerical simulation on fluid-induced vibration of thin elastic plate was carried out. The results reveal that，on the one hand, the swirling flow of different scales comes into being due to the eddy shedding upstream and the disturbance of plate vibration downstream, on the other hand, the fluid-induced vibration is quite significant for wake flowing fields and the elastic plate shows a non-periodic and an asymmetric coupled vibrating behavior when the complex wake interacts with the plate.