Abstract: The cable core and the cable connection tube belong to typical tube/rope connection structure. During the long-term operation, the cable joint needs to have good joint resistance and mechanical strength. An electromagnetic welding device was used to connect the cable connection tube and the 70 mm² cable core, and the core fracture problem during welding of cable joint was studied. The magnetic collector structure and working area length of the electromagnetic welding device were simulated and optimized by Maxwell electromagnetic field analysis software. The results show that when the structure of the magnetic collector is T-shaped, the magnetic induction intensity in the center of the working area can reach 32.10 T. When the working area length of the magnetic collector is 27, 18 mm, the cable joints are in good contact, the joints’ resistance can be stabilized below 40 μΩ. A wave-shaped welding interface is formed between the connecting tube and the wire core, which realizes the integrated connection of the connecting tube and wire core.