Abstract: The method of rapid prototyping oriented by jet electroforming has been used to prepare bulk nanocrystalline copper under the condition of pulse current.The effects of pulse current frequencies and peak current densities on the surface morphology,microstructure,grain sizes and mechanical properties of the copper deposits have been studied.Bulk nanocrystalline coppers with grain sizes in the range of 32-65 nm could be fabricated under the condition of high current density.The deposits of copper with fine grain sizes and smooth surfaces could be got by increasing pulse current frequency and current density.The maximum tensile strength of the nanocrystalline copper reached to 590 MPa,about 4.5 times of the one of the coarse crystalline copper.The maximum tensile elongation of the nanocrystalline copper reached 10%.