The interfacial tension of Ni-plating solution+CO₂ was measured by using the capillary rise method, which is requisite as a basic research for researching new electroplating using macroemulsion in supercritical CO₂. The synthesized surfactant was sodium salt of bis(2,2,3,3,4,4,5,5-octafluoro-1-pentanol) sulfosuccinate which has CO₂ philic chains and hydrophilic head group, and the experimental systems were water+CO₂ and Ni-plating solution+CO₂. In measuring the interfacial tension of Ni-plating solution+CO₂, the effects of surfactant and ethanol were investigated. The interfacial tension of this system was decreased as the surfactant and ethanol were added into Ni-plating solution for Niplating solution+CO₂ system, respectively. However, the interfacial tension of this system at constant temperature was increased as both the surfactant and ethanol were added into this solution simultaneously. This research is useful to select the proper surfactant and additives, and is effective to understand the interface phenomena between CO₂ and polar chemicals such as water or Ni-plating solution for forming the micro-, and macroemulsion in the range of low pressure to supercritical state.