The Thermal Barrier Coating (TBC) System becomes a standard application in gas turbine hot gas path parts to achieve the higher reliability in higher temperature engines. Mitsubishi Heavy Industries, LTD. (MHI) is employing the TBC system on the gas turbine blades, vanes and combustor parts, as to operate in the combustion gas temperature up to 1500C, which results without any spallation or any other damages after several years in actual operations. In the first section, the TBC system in MHI engine is introduced. The TBC system consists of MCrAlY as a bond coat and YSZ (Yttria Stabilized Zirconia) as a top coat. The bond coat is applied by LPPS (Low Pressure Plasma Spray), HVOF (High Velocity Oxygen Fuel) or APS (Atmospheric Plasma Spray) system, and the top coat is applied by APS system. In the second section, some TBC’s performance results in the MHI’s actual engines are described.