Objective To propose the methods to prepare coatings on large-area and complex-shape cathode by discussing the breakdown processes. Methods The coatings were prepared by adding surfactant and H2PtCl6?6H2O in solution. The current density-voltage curves were measured and used for analysis of the discharge mechanism of gaseous film. The surface and cross-section morphologies of the coating were studied by SEM. Results Adding surfactant into solution or adding beads in cathode region could result in more even gaseous film and meanwhile decreased the current density. With increasing Pt content, the porosity of coating was gradually decreased. The fracture toughness and spallation resistance of ceramic coating were improved because of the toughening effect of Pt particles. Conclusion The ceramic coatings could be prepared on large-area and complex shape samples by cathode plasma electrolysis deposition, and the compactness of ceramic coating was improved by dispersing Pt particles.