In this study a numerical model was developed to simulate the wave run-up and overtopping as a solitary wave attacks a seawall near the beach. The Reynolds Averaged Navier-Stokes equations were solved to simulate the viscous, incompressible fluid flow. The hybrid particle level set method (Enright et al., 2002) was applied to capture the evolution of complex free surface, such as wave run-up or overtopping near a seawall. The traditional level set method (Osher and Sethian, 1988) and the innovative immersed boundary method (Lin et al., 2010) were combined to mimic the arbitrary solid boundary and its corresponding boundary conditions on a fixed Cartesian grid system. To verify the accuracy of the presented numerical model, run-up of a solitary wave on a slope bed was simulated, and the numerical results were compared with the experimental data. After having demonstrated the accuracy of the numerical scheme, the developed computer code was applied to study the run-up and overtopping of a solitary wave near a seawall located at the east coast of Taiwan.