Abstract: Resistance heating metal wire additive manufacturing technology is of great significance to the repair and manufacturing of space equipment. During the melting and deposition forming process of resistance heating metal wire, the plastic deformation of the metal melt affects the forming morphology of metal parts. In order to accurately explore the plastic deformation of the metal melt, the plastic change of the metal wire was observed through a high-speed camera when passing different current densities through the short-circuited metal wire. The changes of temperature and electricity signal were collected by using a thermal imager and a voltage and current acquisition system during the melting process. The electromechanical and thermal response states of metal wire plastic deformation were analyzed numerically. The results showed that the maximum deflection obtained by numerical calculation was a linear function of current density, which was consistent with the experimental results. Metal wire passing through high-density current of metal wire occurred significant plastic deformation. Under the action of a high current density current, releasing a large amount of Joule heat caused a significant increase in local temperature and a decrease in yield stress. Due to the electro-thermal-mechanical interaction, it was easy to cause plastic deformation in electronic interconnection.