Abstract: On the basis of experimental and theoretical calculation, this paper analyzes and discusses the vibration and sound radiation of Underwater ribbed cylindrical shell, which is coated with a kind of isolated sound and decoupled material, At first, it offers an experiment, which has three working conditions and its results contains the structural vibration responses and the radiated sound pressure levels. When analyzing it theoretica lly, FEM and BEM are used to calculate the model in low frequency, and the statistical energy analysis(SEA) is used to calculate in medium and high frequency. After the experiment results and the calculation result a analyzed and compared, it shows that the isolated sound and decoupled material can reduce the structural vibration and radiated noise clearly above 200 Hz. It can also be found out that the FEM and BEM result can accord with experiment result only under 700 Hz. It concludes that the FEM and BEM are fit to calculate the complex structure in low frequency and SEA in medium and high frequency.