The simulating waves nearshore (SWAN) model has typically been designed for wave simulations in near-shore regions. In this study, the model’s applicability to the simulation of typhoon waves in the South China Sea (SCS) was evaluated. A blended wind field, consisting of an interior domain based on Fujita’s model and an exterior domain based on Takahashi’s model, was used as the driving wind field. The waves driven by Typhoon Kai-tak over the SCS that occurred in 2012 were selected for the numerical simulation research. Sensitivity analyses of time step, grid resolution, and angle resolution were performed in order to obtain optimal model settings. Through sensitivity analyses, it can be found that the time step has a large influence on the results, while grid resolution and angle resolution have a little effect on the results.