The interaction between the intake tower, working bridge, reservoir water and foundation is complex under seismic actions. The integral finite element model of the tower body-hoist chamber-working bridge-foundation -reservoir water was established, with which the interaction between the structure and reservoir water was simulated based on the potential fluid theory, and the foundation radiation damping effect was investigated using the viscoelastic artificial boundary. In turn, the effect of dynamic interactions between structure, reservoir water, working bridge and foundation on the natural vibration characteristics and seismic response of the integral intake tower system was studied. The results show that the downstream displacement and acceleration of the intake tower can be reduced by 25.15% and 14.33% respectively, and the maximum tensile stress of key points of the intake tower can be reduced by more than 12.0%, with the presence of the working bridge at normal water level. The dynamic response of the intake tower structure is obviously reduced when considering the foundation radiation damping effect, and the maximum tensile stress of the key point can be reduced by more than 40%. Compared with the working bridge, the foundation radiation damping effect has a more significant influence on the hydrodynamic pressure, acceleration, displacement and stress response of the intake tower under seismic actions.