Traditional aero-engine thermal barrier coatings (TBC) mainly focus on thermal insulation properties and reliability, and YSZ-based TBC is already well-developed technology. Yet its electrical properties under elevated temperatures is missing. On the other hand, due to the need to build sensors on turbine blade, study on electrical insulation of TBC is necessity. In this paper, the electrical properties of YSZ thermal barrier coatings at high temperature were studied, and a new YSZ spraying formula is proposed that its high temperature electrical insulation performance. Experiments show that adding a certain amount of alumina into the coating can improve the electrical insulation performance at high temperature by four orders of magnitude, and can meet the practical needs to embed MEMS sensors on the surface of turbine blades. In addition, the electrical properties of the metal/TBC/metal sandwich structure at high temperature have been analyzed by computer simulation. Sensor performance is a composite function of the electric conduction properties under high temperatures as well as size and dimensions of each layer.