Recent study has shown that electron flow would induce a non-uniform lattice strain along the strip and the electric current stress-induced deformation is suggested to have the same context with the conventional solid mechanics' theory. The electromigration (EM) effect is thus suggested to be a local stress relaxation at the condition beyond the critical point. In this study, in situ current stressing experiment with synchrotron radiation-based XRD and in situ SEM equipped with EBSD system were employed to investigate the electric current-induced plastic deformation. The results revealed that at a relatively higher level of current density and the corresponding lattice strain, twinning accompanied with the voids/hillocks formation would be found. When slightly decreasing the current density, no twinning but only voids/hillocks formation could be found. The authors hope this study will advance the knowledge of electric current-induced plastic deformation and provide a further guideline for EM-resistant materials.