Abstract: Based on the structural FEM and the acoustic BEM, a numerical model of coupled elastic layer and vis-coelastic layer and outside sound field is established and the vibro-acoustical characteristics of damped composite shells are studied systematically. It can be concluded that the structural vibration responses and the sound radiation are reduced significantly due to the viscoelastic layer and its effects are dependent on the geometric, physical parameters of the layer and the exciting force frequencies. It is also shown that, compared with the bare elastic shells, the influence of the fluid compressibility on the vibration responses of shells covered with a damping layer is not evident and the effects of the free surface and the rigid plane are weakened.