Samchunpo(Sinhyang) Harbor is located at the Sachun bay, on the central south coast of Korean peninsula. The harbor and coastal boundaries are being protected by natural coastal islands and shoals. Currently, The Shinhyang harbor needs maintenance and renovation to the weather deterioration and typhoon damages on the sheltered structures. Consequently, the calculation of accurate design wave through the typhoon wave attack is necessary. In this study, calculation of incident wave condition simulated by steady state spectrum energy wave model (wide area wave model) from 50 years return wave condition. And this simulation results in wide offshore area were used for the input of the extended mild-slope wave model at the narrow coastal area. Finally, the calculation of design wave at Sinhyang harbor entrance was induced by Boussinesq wave model (detail area wave model) simulation. The numerical model system was able to simulate wave transformations from generation-scale to shoreline or harbor impact. We hope to contribute from this study that coastal engineers are able to assist in the placement, design, orientation, and evaluation of a wide range of potential solutions.