One of the main purposes for studying waves and their resulting phenomena in a harbor is the prediction of harbor tranquility which gives the workable limit of a harbor. Ship activities within a harbor consists of entering the harbor, mooring, and cargo handling. In cases where cargo handling is not possible, the shipping expenditure becomes a large waste of money. And also the development of a harbor causes the circulation reduced inside the harbor and the unbalanced sediment budget of beach results in an alteration of beach topography. Therefore it is needed to predict the effect of the environmental change because of development and so the prediction of wave transformations does. In this study, we will show a numerical method using the time-stepping hyperbolic mild- slope equation involving refraction, diffraction and reflection, and the surfzone energy dissipation term due to wave breaking is included in the basic equation. Numerical model is established by a finite difference method and applied to the port development plan, Ilgwang harbor, at the east coast of Pusan.