Abstract: Based on the acoustic-structural coupling method, the modal characteristics of a molten salt storage tank in a commercial 50 MW tower-type concentrated solar power (CSP) plant were simulated. The influence of anchoring methods on the sloshing characteristics of molten salt storage tanks under full liquid level conditions was investigated, and the effects of parameters such as different liquid levels and operating temperatures on the modal frequencies of unanchored molten salt storage tanks were explored. Results show that the first three orders of unanchored molten salt storage tanks under full liquid level are prone to rigid-body displacement modes, and the sloshing frequency values of the 3rd to 20th orders differ significantly from those of anchored tanks. Therefore, the unanchored configuration is more suitable for modal analysis of molten salt storage tanks. The sloshing frequency of the tank increases with the rise of liquid level under different liquid level conditions, and the sloshing frequency of each order is lower than the natural frequency of the empty tank. The natural vibration period of the empty tank ranges from 0.06-0.1 s, while the sloshing period is as long as 2-15 s, indicating that the sloshing frequency of the tank in the salt-filled state is highly susceptible to resonance under the excitation of long-period seismic waves. Operating temperature has little effect on the sloshing frequency of molten salt, but preheating temperature has a significant impact on the natural frequency of the empty tank. When the operating temperature increases by 100 K, the highest-order natural frequency of the empty tank only decreases by 2.5%. To avoid instability of large-capacity molten salt tanks under the action of high-frequency seismic waves in the preheated state, the influence of preheating temperature on the frequency of empty tanks should be taken into account in the seismic design of molten salt tank structures in practical engineering.