Abstract:Abstract: Based on classical thin-shell theory, the differential equations of vibrations of cylindrical shell with free layer damping were received. The sound transmission loss was derived by conjoining the sound wave equation for the fluid field, and boundary conditions at the fluid-structure interfaces. A corresponding numerical example is given in the paper. And the characteristic of sound transmission of cylindrical shell with viscoelastic layer coating was analyzed. Also the effects of incident wave angles, damping thickness, cylindrical shell radius and thickness on the curves were shown.