Abstract: In order to identify the effect of different displacements on the brine displacing concentration and cavity form in the process of dissolving cavity, the dissolution velocity formula is deduced and transformed to analyze the correlation between the displacement and brine displacing concentration and the cavity volume. Then, using WinUbro cavern numerical simulation software, an ideal cavity model is established and used for comparative analysis under certain assumptions. To verify the reliability of the conclusions, the data of cavity wells in Jintan are collected, and compared and analyzed for each stage of dissolving cavity; detailed analysis is made for typical phase of some wells, deriving the conclusion which is consistent with results of theoretical analysis, namely, the smaller the freshwater displacement is, when dissolving the cavity, the higher the brine displacing concentration and the more regular the cavity form are.