Abstract: Due to the phenomenon that difficulties in applying bolt preload, low conversion efficiency and applying high torque at the rear of anchor rod nut forming damage and leading to bolt tail prone to breakage, reducing the overall strength of the supporting bolt, we use laboratory tests and field trials of the method to study the effect of preload thrust ball bearing in conversion efficiency, matching relationship with the different forms of thrust ball bearing nuts, and a new type of anti-friction way underground industrial test, draw thrust ball bearing torque conversion efficiency than doubled nylon washers and bolt preload high torque at smaller. When the thrust ball bearing diameter and bolt diameter difference is 1 mm, bearing high compressive strength, using the bearing flange nuts may force more evenly. Practice has proved that the thrust ball bearings in the underground stable performance, greatly improves the bolt supporting strength and support stiffness, and the reliability of support system.