A new electrolytic technique using an atmospheric pressure plasma was attempted for the anodization of copper. The anodization was achieved by plasma electrolysis using deionized water as a sole electrolyte with a support of atmospheric plasma. The atmospheric pressure plasma was assigned as a cathode and induced the cathodic reaction in contact with liquid surface while the anodic reaction occurred at the copper plate. After the plasma electrolysis for 180 seconds at discharge voltage of 5 kV, a polyhedral structure started appearing on the surface of copper electrode and grew as the anodization time increased. The longer electrolysis over 420 seconds, however, induced dissolution of the as-formed structure because of destruction of the as-formed layer. These phenomena were considered to be caused by change in the properties of deionized water during the plasma electrolysis. The plasma-water interaction had an effect on the conductivity, pH and temperature of deionized water which determines the phase of the metal electrode in the electrochemical system. (C) The Author(s) 2019. Published by ECS.