This paper presents the numerical simulation of storm surges including wave-current interactions based on the 3D nearshore current model. The current model included new terms on surface stress and wave-induced Reynolds stress. Nearshore current field under storm surge was calculated with wave forcing terms including surface roller. The present model is dynamically coupled with shallow water wind wave model. We conducted storm surge simulations in Youngil-bay located in the east coast of Korea. The purpose of this simulation is to estimate the influence of large breakwater in the bay entrance on the beach erosion located inside bay during the storm.