Shaking table tests of a caisson seawall model were conducted to investigate sliding phenomena of the seawall. The response characteristics of the caisson placed on the mound which was fixed to the shaking table were investigated in the six series of experiments with varying the situation of the model; with or without backfill, wave breaking works and water. These test results were utilized to validate a two-dimensional FEM analysis method with joint elements. The numerical model with the finer mesh division and joint elements showed fairly close results with the series of test results, resulting the better representation of the characteristics of sliding and plastic deformation nature of the seawall model