Abstract: Abstract: Outlet tower of pumping station is a tower structure connected to the pumping station pressure pipes and downstream aqueduct. In order to ensure the safe operation of the structure, it is necessary to analyze its seismic response. Taking second stage sixth pumping station outlet tower of Jingtaichuan project as the research object, the large FEM software ANSYS was used to establish the massless foundation model and the viscoelastic boundary model of outlet tower based on fluid-solid coupling effect and elastic wave theory. First, combining the efficient and accurate modal calculation method, the modal analysis of the water tower system under 2 conditions of with water or not was carried out. The measured datas of the outlet tower was treated by the shock-resistant DP seismic low frequency vibration transducer. Furthermore, the CEEMDAN-SVD method proposed by author was used to filter strong background noise and extract the vibration feature information of each measuring point of the structure. The information fusion method of variance contribution rate was used to dynamically fuse the signal after denoising of measuring points, and the complete work feature information of the water tower was obtained. Then, the natural vabration frquency of the water tower structure was extracted and the vabration frquency was compared with the dry and wet modals of the fluid-solid coupling model. The rationality of the established fluid-structure coupling model and the effect of the aqueous medium on the natural vibration characteristics of the outlet tower system were verified. Subsequently, based on the identification and modal analysis conclusions, according to the location of the project, the Lanzhou wave was selected as the seismic input time-history of the dynamic response analysis. The three-way seismic wave time-histories were inputted simultaneously to both the massless foundation model and the viscoelastic boundary model under the conditions of with water or not. The results of the relative displacement time-history and the maximum value of tension-compression stress of node A under 2 operating conditions was compared, and the influence of the interaction among the water-structure-foundation coupling system was analysied. The results showed that, comparing dry and wet modal calculation results with CEEMDAN-SVD identification results, it can be seen that the working frequency of the outlet tower is 3.3 Hz, and the water reduces the modal frequency of the tower. Through the analysis of the displacement and stress responses, it can be seen that the condition 1 is an unfavorable working condition. Compared with the results of the massless foundation, the displacement response value of the viscoelastic boundary results is reduced by 38.5% and its stress response value is reduced by 37.8%. The maximum displacement response of the condition 2 is 63.8% which is lower than that of condition 1, and the maximum stress response reduces by 73.1%. In the models of this paper, the effects of water and viscoelastic boundary on the seismicity of the outlet tower are opposite. When the water and viscoelastic boundary were considered at the same time, the seismic displacement and stress response results under the condition of massless foundation with waterless are smaller than those of with viscoelastic boundary and water condition. These results indicated that the water body has greater impact on the seismicity of water tower and is more important. The water increases the seismic response during the calculation of seismic response of water tower, and it should not be neglected. For the selection of foundation conditions to calculate the seismic response of water tower, the massless foundation is safer, and the viscoelastic boundary foundation which considering the infinite foundation radiation damping is recommended.