Abstract: To prepare Ni-Fe ultrafine powder with good sphericity and high purity, a non-contact wire electrical explosion powder making device was used to conduct experiments, which were carried out in an argon atmosphere using 0.4 mm diameter Ni-Fe wire at different charging voltages. Simultaneously collecting and analyzing the waveform of electrical explosion discharge of Ni-Fe wire and the variation pattern of deposition energy. A time-varying nonlinear resistance model of Ni-Fe wire electrical explosion is developed and compared with the experimental curve for analysis to investigate the mechanism of Ni-Fe wire electrical explosion. The powder morphology is observed by scanning electron microscope to investigate the effect of Ni-Fe wire electrical explosion process parameters on powder morphology and particle size. The results show that the wire voltage, deposition energy and discharge circuit current peak gradually increase with the increase of charging voltage, and the breakdown moment along the surface is gradually advanced. The wire resistance model can reflect the actual resistance change, and the degree of compliance with the experimental curve is good. Superfine powder with good sphericity, uniform particle size distribution and high purity can be produced under the process parameters of charging voltage of 11-15 kV.