Abstract: Stiffened cylindrical shells are major structures of submerged vessels. Approximate analytic solution is derived for the vibration and sound radiation from a stiffened finite cylindrical shell in water,.supposing the action of a stiffener on shell is only the normal force.In this solution an additional impedance caused by the stiffeners is added to the coupled vibration equation. As a result, the vibration and sound radiation of shell are dependent on the mechanical impedance of shell, the radiation sound impedance and the additional impedance. Numerical results show that stiffeners have no important influence on radiated sound power, while decrease surface average velocity and increase radiation efficient.