Abstract: The change of salt-cavern injection-production cycle leads to the periodic change of cavern temperature, and then the periodic change of thermal stress of surrounding rock. The tensile strength of salt rock is low, so when the periodic thermal stress is tensile stress and its value is higher, salt rock will be broken, resulting in cavity collapse. In this paper, cavern shape and volume data measured by sonar under pressure were used. By virtue of finite-element numerical simulation, a thermal stress model was established by coupling the temperature field with the existing mechanical model. Then, the conventional model and the thermal stress model were compared to analyze the influence of thermal stress on cavern stability. It is indicated that some stable zones in the conventional model suffer collapse in the thermal stress model. The calculation results of thermal stress model are in accordance with the values measured by sonar under pressure, so it is inferred that the thermal stress generated by temperature change is the main factor influencing cavity stability and may even lead to cavity collapse. To sum up, the proposal of thermal stress as the influential factor makes the cavity stability evaluation system more complete and the evaluation results closer to the real strata situations.