Cup-shaped parts with different thin-walled thickness structures are an essential transmission component for the harmonic reducer in aerospace and intelligent robotics engineering. However, those cup-shaped parts are usually prepared from a difficult-to-deform metal with high deformation resistance and poor plasticity at room temperature. This paper explores a current-assisted flow spinning (CAFS) method to reduce deformation resistance, improve plasticity, and promote grain refinement through electroplasticity. To reveal the mechanism of pulse current on macroscopic and microscopic deformation mechanism, a finite element model coupled with the electroplasticity effect is constructed; an experimental platform for the current-assisted flow spinning is set up, and a series of process experiments are carried out. The results show that the current density of the cup-shaped blank is concentrated near the contact area of the roller, so the softening region, due to the electroplasticity effect, highly overlaps with the deformation region of the cup-shaped blank. Thus, as the current intensity increases, the stress and the dangerous area of the cup-shaped part decreases, improving the forming quality of the spun workpiece. In addition, the gradual decrease of the current density along the axial direction from the mouth to the bottom makes the grain refinement accelerated by the electroplasticity effect at the mouth higher than that at the middle, which partially eliminates the uneven microstructure along the axial direction caused by the uneven deformation. The tensile strength and hardness of the spun workpiece under pulse current conditions increase by 8.49 % and 7.42 %, respectively. These findings provide an important theoretical basis for the current-assisted forming process to prepare high-performance and high-precision complex components made of difficult-to-deform metal.