Ultrafine copper powder is widely used in the fields of electronics, lubrication, catalysts, due to its large specific surface area, excellent thermal conductivity and high surface activity. The ultrafine copper powder?s application performance is determined by the control technology of spherical, uniform particle size, monodisperse and high purity. The ultrafine copper powder was prepared by high frequency hydrogen plasma enhanced reduction with characteristics of simple operation, high purity, controllable atmosphere and less environmental pollution. The free radicals produced by hydrogen plasma arc was helpful to control the morphology and the particle size of copper powder. The feeding rate, reducing hydrogen flow rate, hydrogen distribution position, reaction zone space, cooling temperature, and the optimal process conditions were determined, and more uniform and well dispersed ultrafine spherical particles were prepared with particle size mainly between 100 and 200 nm. The oxygen content was under 1%, bulk density was 0.502 g/cm3.