Abstract: Molten salt thermal storage is most widely used in the concentrating solar power system. To further research the high-temperature molten salt tank, a large-scale molten salt tank with the salt storage volume of 1.65×10⁴ m³ was designed by variable point design method, which was specified in API 650 standard. Temperature distribution of the large-scale molten salt tank was simulated by computational fluid dynamics software of Fluent. Structure static analysis of the tank was conducted by using the finite element software of ABAQUS. Finally, the effect of temperature gradient on the thermal stress was verified through the thermal stress analysis of molten salt tank simulation by the sequential coupling method. At the same time, stress evaluation of the tank was calculated based on the 3rd strength theory of material.