Abstract: In order to solve the technical problems of testing items such as hydraulic support yield performance and base specific pressure, as well as the inability of existing hydraulic support testing devices to perform external loading, This paper designs a movable hydraulic support external loading and specific pressure testing device. This device uses 12 gas-liquid combined functional loading cylinders as external loading power sources and specific pressure testing data acquisition components, which can be respectively used for external loading and base specific pressure testing. During external loading testing, the multi cylinder synchronous loading based on high-precision rigid hydraulic synchronous cylinder adjustment technology is used to achieve the external loading function of the testing device; During the specific pressure test, the specific pressure distribution value is obtained according to the relationship between the "Gas Spring" settlement displacement and pressure data of different sections when the test device is loaded with external load. By conducting shrinkage performance and specific pressure tests on different specifications of hydraulic supports on different test rigs, it was found that the external loading test process was smooth and the specific pressure test data collection was fast and accurate. Actual testing has shown that the device has the function of shared use among different hydraulic support testing devices, which can effectively solve the technical problems of external loading and specific pressure testing of hydraulic supports.