The seismic design for the gravity quay wall is an important research for hydraulic structures. A 2D numerical model,representing PC1 berth located in Port Island,Kobe,which was damaged in the 1995 Kobe earthquake,is developed by ABAQUS to simulate the seismic behavior. This paper considers the interaction between soil and structure,and the role of wave filtering by infinite element boundaries. The results show that the horizontal displacements and vertical settlements at caisson top’s sea side are 2.53 m and 1.11 m respectively. Compared with the measured data,the error is controlled within 1.7%. This verifies the accuracy of the model. The plastic damage in the foundation is the main reason for the structural damage. Soil under the front toe of caisson is stress concentration area and should be paid attention to. The peak equivalent stress in this area,which shall be paid attention to in the seismic design,reaches 0.8 MPa.