Abstract: Finite cylindrical shells with stiffened ribs are major structure of cabin on the submerged or underwater vehicles. It has important theoretic value and practicality to research sound-vibration charact-eristic of the finite cylindrical shell with stiffened ribs. On the basis of experimental and numerical calc-ulation,this paper studies the vibration and sound radiation of underwater ribbed cylindrical shell. Test model is coated with a kind of isolated and sound decoupled material. In four working conditions the vibration passing through the two shells and the radiated sound pressure are analyzed when the model is shocked by a single frequency. The result indicates that the brace has a great contribution towards vibr-ation passing. Vibration and sound radiation are controlled effectively when the shells of the model are all coated with the isolated and sound decoupled material. A composite brace structure (including quadrate steel) is presented in order to reduce the influence of the brace on the vibration and sound radiation. The acoustic characteristic of double cylindrical shell including quadrate steel beam is analyzed as well. It shows that the quadrate steel beam can reduce the vibration and sound radiation of the underwater cylindrical shell effectively.