Abstract: In order to evaluate the fiber/matrix interfaces in a fiber reinforced composite, this paper pres sents a mathematical algorithm for predicting the scattering cross section of a cylindrical three-layered medium and the sound attenuation due to the scattering in the composite. When the thickness of the fiber/matrix interface layer is small compared to the wavelength, two stiffness constants are used to simulate the boundary conditions and a simplified method for predicting the sound scattering is developed. Numerical compunctions have been made for the relations of longitudinal wave attenuation coefficients in a glass fiber/aluminum composite with the interface properties and wave frequencies.