Abstract: In order to improve the backward status of hand operation for the height adjustment of the present hydraulic powered support test rig, a completed set a utomatic height adjustment hydraulic system was designed for the powerful hydraulic powered support test rig.A high accurate gear difluence motor of the system was applied to provide the matched flow for the four height adjustment cylinders and the bypass throttle adjustment mode could be applied to the automatic height adjustme nt.During the height adjustment, the displacement sensor could be applied to timely feed back the height difference between the four cylinders.When the height differen ce reached at the set value, the relative bypass throttle adjustment could be timely controlled to eliminate the lifting platform jammed occurred.The site actual applicatio n showed that the system would have an automatic lifting function of the powerful hydraulic powered support test ring.The height adjustment speed could be controlled at 510 mm/s and the final aligning accuracy to the borehole could be 1 mm.