The shape of the salt cavern is very important for the safe operation of gas storage facilities in rock salt. A physical simulation test is an effective means to study the shape control of salt caverns. To accurately simulate the process and parameters of single-well solution mining in rock salt, we developed simulation technologies and a testing system for cavern shape control. Based on the flow similarity principle, we established a sealing technology for dynamic-static disturbance and successfully replicated the solution mining process for forward and reverse circulations. Based on the requirement of protective fluid in the field, we developed a protection liquid unit to control the oil pad height to avoid overdissolution or uneven dissolution at the top of the salt cavern. From the principle of distance determination by laser and video, we developed a salt cavern shape visualization and micro-distance detection system that can realize the size measurement and real-time visualization of the salt cavern in pressurized corrosive environment. We put forward the control technology of the testing system that can achieve the integrated and collaborative control of inner and outer pipe spacing, water flow during injection-production circulations, and the height of protection fluid. Finally, we carried out a physical simulation test of solution mining for cavern shape control. The shape and size of the salt cavern from the test are in good agreement with the design. This study can provide an important basis for determining the optimal solution in mining technology and the parameters for cavern shape control.