Copper nanoparticles are prepared by electrochemical method with various current density in emulsion containing sodium dodecyl sulfate, tween80, dodecyl mercaptan, CuSO4 5H2O. The resulting copper nanoparticles are investigated by XRD, TEM and FT-IR. The result shows that great changes have taken place in the size, the dispersibility, and the distribution of particles size as the current density goes up. According to analysis, it can be found that the copper nanoparticle can be obtained in smaller size, better dispersibility and narrower distribution of particle size under the current density of 0.01 A/cm². At the same time, current density eventually affects the size of the nanoparticles as well as overpotential and the size of water droplet.