Abstract: To make full use of the limited salt resources in the area of Jintan salt mine and maximize the total cavity volume of the whole Jintan gas storage, it is necessary to select the cavities whose diameter can be increased appropriately in the cavity building wells, and then optimize their volumes. In this paper, three types of cavities whose diameter cannot be increased were firstly excluded, including the one to be completed soon, suffered from serious partial solution, or with minimum pillar/diameter ratio (P/D) less than 2.3 in its adjacent cavity. Then, based on the evaluation of its adjacent cavity, 10 cavities were selected from 26 cavity building wells. Finally, the cavity volume was simulated again after its maximum diameter was determined. After the optimization, the total volume of 10 cavities is increased by 26×10⁴ m³. Thus, not only the limited salt resources are utilized fully, but also the solution mining cost is cut down. The research result provides the theoretical guidance for the construction of other salt-cavern gas storages in future.