The applicability of the VOF method to wave motions was investigated by using a computation model, ‘CADMAS-SURF’, providcd by Costal Development Institute of Technology. First, simple linear and non-linear regular waves were calculated with several combinations of different sizes of cells and time steps, and the numerical results were compared with theoretical ones. It was found that the reproducibility decreases as the wave height increases. Next, random wave run-ups along a vertical seawall were calculated, and the results were compared with the experimental results obtained by model experiments using two-dimensional wave tank. It was also found that the VOF model can roughly reproduces the wave run-up, but the model cannot reproduce the intense wave run-ups in detail.