Abstract: The finite element method is applied to analyze sound characteristics of the viscoelastic layer containing periodic cavities when it is immersed in the water or adhered to a steel flat between water and air. The results show that the reflection coefficients of the viscoelastic layer with periodic cavities are bigger than that without cavities at low frequency. The resonance of cavities can affect the sound characteristics. Moreover, numerical results are obtained for the viscoelastic layer with spherical, cylindrical or cone-shaped cavities and the modes of their vibrations are analyzed.