YAG (Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>)-Al<sub>2</sub>O<sub>3</sub>-Pt composite TBCs have been prepared on Ni-based superalloy (0.1% C, 12% Co, 6.5% Cr, 6.2% Al, 5% W, 1% Mo, 1.5% Hf, 6.5% Ta, 0.01% B, balance Ni, wt.%) by cathode plasma electrolytic deposition (CPED). As polyethylene glycol (PEG) is added in solution, the spark ignition current density is reduced significantly, and CPED would be a promising technique to deposit the uniform coatings on large-sized cathode. The cyclic oxidation tests at 1100°C reveal that the high temperature oxidation resistance of such TBCs are significantly improved by dispersing Pt particles. These excellent performances can be attributed to the effects: the low porosity of coating can inhibit further oxidation of alloy substrate, the toughening role of Pt particles and the stress relaxation caused by the deformation in the porous structure can improve the mechanical properties remarkably. The spallation resistance of YAG-Al<sub>2</sub>O<sub>3</sub>-Pt composite coating can be significant improved by using the following two method: one is adding PEG 20000 to the solution during the CPED process; the other is using Pt particle to toughness the coating. In addition, such YAG-Al<sub>2</sub>O<sub>3</sub>-Pt composite coatings possess quite well thermal insulation owing to the thermal insulation capability of YAG and the structure of vertical block micropores.