Abstract: In order to study the dynamic characteristics of deepwater piers and the distribution of hydrodynamic pressure on them, a pier-water coupling vibration test was conducted. By comparing the experimental results with the ANSYS-CFX calculation results, the effectiveness of the experimental data is verified. By numerical fitting, the variation of hydrodynamic pressure with varying pier section and depth is obtained. The elastic vibration of deepwater pier is simulated by using the additional stiffness method. It is shown that the calculation results from the additional stiffness method are consistent with the experimental results and the stiffness method can explain the experimental principles. The fundamental frequency of the pier increases with the increased depth; in addition, the response of the pier decreases with the increased depth. The additional stiffness method can be used to simulate the pier-water coupling vibration effectively.