In inert gas, pure Ni nanopowders were prepared by anodic arc discharged plasma method utilizing self-designed and fabricated experimental apparatus, and the influence of arc current and gas pressure on the production rate and particle size of metal nanopowders in the process was studied. The product was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and the corresponding electron diffraction (ED) to determine the morphology, crystal microstructure, the size and size distribution. The experiment results revealed that Ni nanopowders with particle size range from 20 nm to 100 nm can be obtained by using the suitable controlled experimental apparatus. The production rate and particle size increase with raising arc current or gas pressure when other factors are fixed. The crystal structure of Ni nanopowders is the same as the bulk materials, is fcc phase.