Abstract: Sound radiation from a submerged elastic cylindrical shell excited by internal harmonic line force is considered. It is useful for understanding the mechanisms of sound radiation from submerged structure and verifying the Resonance Radiation Theory (RRT). Firstly, the resonance radiation formula is derived from classical Rayleigh normal mode solutions, then numerical calculation for a thin steel cylindrical shell is completed by using these two methods. The results of RRT solutions are compared with that of Rayleigh series solutions, which are in good agreement.