The interaction between interlayer and brine migration in cavity construction period is analyzed by taking the Jintan underground energy storage of salt rock in Jiangsu Province as a demonstration project and using RNG k〖XC半字线.tif,JZ〗ε turbulence model and material transfer theory. The study shows the movement of brine in the cavity construction process forms complex turbulences due to the affecting of interlayer. Vortexes are produced around the interlayer and their influence diminishes with the expansion of chamber. Additionally, the influence of the interlayer on flow field is also affected by washing techniques, such as water injection method, location of injection flow rate and spatial location of casing. At the same time, the non uniform flow of brine forms different degrees of water pressure on the interlayer. Generally, the interlayer is mainly affected by the water pressure generated by injection water flow in the former stage of cavity construction, while it is mainly affected by boundary mass flow in the latter stage of cavity construction. But in both stages, the pressure generated by brine flows is insufficient to make the interlayer collapse. PIV techniques are adopted to monitor migration law of the brine in physical model, and the law of brine movement in experiments is consistent with calculation results.