Abstract: The durability of numerous Cu/Al transition joints in power systems is critical for long-term operational safety. Cu/Al calde electromagnetic pulse welded joints were investigated, and the neutral salt spray and electrochemical corrosion tests were carried out in this study to reveal the performance degradation law and corrosion mechanisms of the welded joints. Electrochemical results reveal that the transition joints exhibit lower corrosion potential and higher corrosion current compared to the base materials, indicating inferior corrosion resistance. Neutral salt spray tests demonstrate that the ultimate tensile load of the joints decreases nearly linearly with aging time, while the contact resistance increases linearly. Tensile fractures consistently occur in the aluminum stranded conductors. In the neutral salt spray environment, the electrochemical corrosion primarily initiates in the overlapping region, starting within the semi-enclosed wedge area. As corrosion products accumulate, the corrosion shifts to the copper tube's port, where the aluminum strands, acting as the anode, undergo severe corrosion, forming pits and reducing the outer diameter. The overlapping zone of the Cu-Al electromagnetic pulse welded joint protects the weld seam, resulting in superior corrosion resistance in the weld region compared to the overlapping area.