Abstract: To monitor the water quality in the deep sea, the study designs a new double-layer coaxial porous cylinder structure from a practical engineering point of view. Considering that the porous structure has a good wave attenuation effect, the model proposed is designed as a double-layer cylinder system with holes on the wall surface of the cylinder. Considering that the actual seabed is porous, the studies of scattering and radiation from an isolated double-layer coaxial porous cylinder structure floating on a porous seabed are theoretically investigated. Based on the assumption of the small amplitude wave theory, the expressions for the velocity potential and free surface elevation of an isolated double-layer coaxial porous cylinder structure floating on a porous seabed are derived using the eigenfunction expansion method and Darcy's law. The unknown coefficients in the velocity potential are obtained by the matching feature function method. To ensure the correctness of the program, the model proposed is reduced and compared with the existing results. After completing the validation, a detailed parametric study is carried out on an isolated double-layer coaxial porous cylinder structure floating on a porous seabed, with a focus on the influence of the porous seabed on the hydrodynamic characteristics of the porous cylinder structure. The studying results can provide a theoretical basis for subsequent studies.