The shape and connection structure of high-strength bolts are basically the same as those of ordinary bolts. The main differences between them are as follows: ordinary bolt connection relies on the pressure and shear of the rod body to transmit shear force, while the pre-tension force produced by bolts is very small when the bolts are tightened, and its influence is not considered; the working principle of high-strength bolt connection is to intentionally exert great influence on the bolts. Pre-tension force causes extrusion force between the contact surfaces of the joints, so there is a great friction force perpendicular to the screw direction, relying on this friction force to transfer the connection shear. The pre-tension force of high-strength bolts is achieved by tightening the nuts. The common high-strength bolts generally adopt the methods of torque and rotation. The Torsion-shear type high strength bolt adopts the Torsion-shear bolt tail to control the pre-tension force. Bolts connected with high strength bolts are made of 10.9S grade or 8.8S grade high quality alloy structural steel after heat treatment. Holes of high strength bolts should be drilled into holes. The diameter of the high strength bolt with friction connection is 1.5-2.0 mm larger than the nominal diameter D of the bolt, and the diameter of the high strength bolt with pressure connection is 1.0-1.5 mm larger than the nominal diameter D of the bolt.