Centrifugal shaking table tests on an old masonry retaining wall model were conducted to clarify the seismic damage mechanism to the residential site with a building. The tests were performed on two retaining walls composed of aluminum bars: a wet masonry retaining wall with solid integrity and a dry masonry retaining wall without solid integrity. Tests and 3D-FEM analyses indicated that the solidity of the retaining wall affects its failure mode and that the dynamic interaction effect between the retaining wall and the backfill soil may cause earth pressure during an earthquake to act on the retaining wall.