Abstract: In view of problems of low efficiency of entering and exiting test bench during hydraulic support inspection and prone to injury accidents, an automatic in and out device of hydraulic support test bench was designed. An in and out trolley is driven by an electric motor to transport the tested support to the designated position of the test bench on a dedicated track; In order to make the tested support transported to the specified position by the trolley, a horizontal lifting cylinder is designed.The lifting cylinder is installed in the base of the test bench to push the wedge-shaped horizontal moving block, the wedge-shaped vertical moving block is driven to move vertically up and down along the track in the base.On the wedge vertical moving block, 16 ejecting rods are arranged according to the size of the U-shaped internal space of the trolley, which pass vertically through holes reserved in the base of the test bench and enter into the tested support on the test bench to make it separate from the trolley. As a result, the trolley exits and resets, and then the tested support is put down to enter test state. Analysis and calculation results show that the rated load of the device exceeds 120 t, which meets requirements of the hydraulic support for automatic in and out the test bench. Practical application shows that the device avoids unnecessary loading of the in and out trolley, realizes the automation of the whole in and out process of hydraulic support, greatly shortens the time for the hydraulic support to enter and exit the test bench, and completely eliminates safety hazards.