Abstract: In view of the difficulty in designing the tightening torque of the thread fastening connection structure widely used in engineering practice, combined with the relationship between pre-tightening force and tightening torque, a typical structure is designed to carry out the torque test of the connecting parts with different lengths of screws and different materials, and the important data such as the bending torque, failure torque, failure angle under the designed structure are obtained. According to the yield torque and the mechanical properties of the screw, the friction coefficient of the contact support surface between the screw and the workpiece after the typical surface treatment is obtained. This test method can be used to realize the rapid design of the thread fastening connection structure, improve the design efficiency and realize the engineering application.