In this study, experiments of a nickel elecroplating were performed in a supercritical nano-plating system using CO₂ as a supercritical fluid. Electrolyte and surfactant were important parameters on the nickel plating process. Resistivity values decreased 60, 35, and 22 Ω at 20, 30, and 50 wt% electrolyte, respectively, and over 60 wt%, the resistivity value was kept constant at 20 Ω. Surface properties of nickel film electroplated by the 60 wt% electrolyte solution with 2 wt% surfactant. The weight ratio of CO₂ and electrolyte as 1:9 was better than any other ratio in the plating properties.