During the assembly process of steel beams, the laborers must stand on narrow steel beams to assemble structures. Locating and bolting are two main steps in the steel beam assembly process. In the locating step, laborers haul and position the steel beam into the target position. In the bolting step, laborers assemble the steel beam with bolts. This manual assembly method can result in potentially fatal falling accidents. The efficiency of the process is also difficult to control. Therefore, we propose an autonomous joint system that will remove the need for laborers to work in elevated positions. The system consists of two subsystems: a steel beam hauling system and a bolting system. In this study, we focus on the design of the steel beam hauling system. The steel beam hauling system can catch the draft cable using an electromagnet and haul the lifted steel beam to the target position. The cooperation between the system and the tower crane is also considered. The system can be attached to each steel column before erection then removed by the tower crane after the assembly process is finished. The system was built in a scaled-experiment construction site to test its feasibility. In conclusion, we propose an autonomous joint system that can help reduce accidental falls and improve efficiency of the steel beam assembly process.