Rock pure shear test system under bidirectional symmetrical compression

The invention belongs to the technical field of rock testing, particularly discloses a rock pure shear test system under bidirectional symmetrical compression, and aims to simplify the structure and save the cost by being matched with equipment capable of providing axial pressure for use. The test system can drive the first main rack and the second main rack to move up and down synchronously through the pressed connecting rod of the power conversion mechanism, so that the test system can be matched with a pressing rod of equipment capable of providing axial pressure through the pressed connecting rod; axial pressure provided by equipment is used as power for driving the first main rack and the second main rack to move synchronously. Under the driving of equipment for providing axial pressure, the power conversion mechanism can drive the left sample fixing head and the right sample fixing head to rotate in opposite rotating directions, so that torsional moment can be applied to the rock sample fixedly mounted