This study aims at the numerical analysis of wave characteristics when a wave propagates on the porous slope seabed. Numerical wave tank technique was developed using boundary element method with constant panels on the boundary. The fluid was satisfied with potential flow conditions and Darcy’s law was applied for porous intersection. Two computational domain method, which consists of fluid and porous domains, was used to simulate the propagating waves over a sloped seabed having a permeability. To consider fluid-porous boundary interaction, three-step boundary value problems were calculated. The wave amplitude decreased along the free surface as the wave propagated over a sloped bottom. The wave reflection and transmission by subsea structures were also analyzed.