Abstract: Numerical analysis of sound radiation from a submerged cylindrical shell excited by interior point source has been carried out by FEM/BEM. The modes of stiffened shells are calculated by ANSYS. A numerical analysis of sound radiation of stiffened shell excited by interior point source is performed by incorporating the modes into the SYSNOISE, and predictions of the sound pressure both in side and out side of the shell are made, and the curve of sound power is obtained as well.