Abstract: In order to meet the needs of radar target detection, recognition, and classification above the land sea boundary area, the composite scattering characteristics of the surface and moving targets above the land sea boundary area were studied. The Monte Carlo method was used to combine PM sea spectrum, TMA sea spectrum, and exponential power spectrum to generate deep water sea surface, limited depth sea surface, and coastal geomorphic surface, respectively. The dielectric constant of seawater and coast was simulated using the medium reflection coefficient chart recommended by CCIR(International Radio Consultative Committee). The composite scattering coefficient of the surface of the land sea boundary area and the moving circular cross-section column above it was calculated using the method of moments, and the angular distribution curve of the composite scattering coefficient was obtained, we analyzed the effects of horizontal and vertical translation of circular cross-section columns on the composite scattering coefficient in deep-sea sea surface, coastal geomorphic surface, and limited depth sea surface. We also analyzed the effects of circular cross-section columns moving to coastal geomorphic surface, limited depth sea surface, and deep water sea surface on the composite scattering coefficient. The numerical calculation results show that the composite scattering coefficient oscillates with the scattering angle, and the longitudinal translation of a circular cross-section column above the coastal geomorphic surface and the deep water sea surface has a significant impact on the composite scattering coefficient. However, the movement of a circular cross-section column above the finite depth sea surface has a complex impact on the composite scattering coefficient, and when the circular cross-section column moves along the surface of the land sea boundary area, the composite scattering coefficient will be greatly affected.