Abstract: The vibro-acoustic analysis is one of the important parts in the spacecraft design. This paper proposes a method to model the acoustic diffusion field by combining uncorrelated plane waves linearly and its justification is shown theoretically. The parameters for each plane wave are also obtained in the paper. After that, a satellite vibro-acoustic problem is simulated using the FEM-BEM method and the results are validated by the test data, which shows that the method is theoretically correct and could be used to analyze the vibro-acoustic response of spacecraft.