Abstract: For the full use of proven high-quality salt resources to build salt cavern gas storage and minimizing the impact of thick interlayer in salt beds on solution mining, it is required to carry out research on solution mining technology under the condition of thick interlayer salt beds. It can be clearly learnt from the cavern building test that, the thick interlayer is likely to collapse during the solution mining process, and the lower salt rock is considered to be capable of cavern building. Based on the geological characteristics of salt beds and the practical experience of cavern building in similar projects in China, the cavity of Huai'an gas storage should be designed in a desirable shape with the top and bottom as an approximately cone and the main body as frustum of a cone with the maximum diameter located at the bottom of frustum of a cone. Based on the drilling data, the cavern building plan was designed and numerically simulated. The idea is as follows: firstly, a positive circulation method should be adopted for cavern building in the salt rock at the lower part of the thick interlayer, and then the cavern building string should be adjusted to simultaneously build the cavern at the upper and lower part of the thick interlayer for accelerating the collapse of the thick interlayer. In the middle and late stage of cavern building, the reverse circulation cavern building method should be adopted to speed up the progress of cavern building. The numerical simulation and practical application show that the solution mining technology could take full advantage of salt rocks in the cavern building areas. The design idea is expected to provide a reference for the treatment of medium and thick interlayer in the cavern building process.