Our country’s salt cavern underground gas storage has complicated geological conditions and more salt-mudstone interlayer. The premise of efficient construction and safe operation of salt cavern gas storage is to optimize the construction area and stratum. In this paper, the composition experiments of target stratum in Pingdingshan, Huai’an, Anning and Chuzhou where are proposed to build salt cavern gas storage are taken as examples. In this paper, the composition of core samples in different layers in different areas is studied by taking the composition experiments of target intervals in Pingdingshan, Huai’an, Anning and Chuzhou salt cavern gas storage areas as examples. The experimental results are classified according to the salt rock and mudstone, the composition characteristics of samples in different areas are summarized. The characteristics of mudstone and salt rock with obvious layering in Pingdingshan area, high salt content in Huai’an samples, high content of calcium sulfate and sodium sulfate in Anning area, and relatively high soluble content of mudstone in Chuzhou area were analyzed and suggestions were made on how these features might affect the construction of water-soluble salt cavern gas storage. Given the characteristics of layered Salt rock in China with many interlayers and high content of insoluble substances, it is necessary to conduct more experiments on increasing the content of insoluble components, which will provide important reference data for further improving the capacity of salt caverns as gas storage facilities by utilizing the void space left by the insoluble residues.