Metal Organic Chemical Vapor Deposition (MOCVD) process is a vapor phase growth technique which is synthesized via vapor phase from metal organic complex material and will become one of the desirable deposition methods to form oxide layer on the complicated shape ducts and large-area walls of breeding blanket components. The single phase erbium oxide (Er2O3) coating layers were able to be synthesized on metal substrates such as stainless-steel 316 (SUS316) and vanadium alloy and Si single crystal plates. In this paper, the hydrogen permeation and electrical property of Er2O3 coating layer via MOCVD process will be mainly reported. The hydrogen permeation quantity of Er2O3 coating layer estimated by QMS was decreased by 1/20 compared with SUS 316 at 400 °C. In addition, the demonstration of Er2O3 coating into the interior surface of the stainless-steel was also succeeded.