Abstract: To reduce the operating temperature of aircraft engine turbine blades and extend their service life, high-temperature and corrosion-resistant protective thermal barrier coatings are applied to the surface of blade. Thinning, peeling, debonding, or uneven thickness of thermal barrier coatings can lead to their failure and inability to protect the substrate material. Therefore, it is necessary to measure the thickness of thermal barrier coatings during the manufacturing and service of turbine blades. The paper proposed a method for measuring the thickness of thermal barrier coatings on turbine blades using ultra-high frequency scanning eddy current testing technology, developed a device of frequency scanning eddy current testing on measuring the thickness of multi-layer coating and measured the thickness of thermal barrier coating on turbine blades. Through experimental verification, it was shown that frequency scanning eddy current testing technology could meet the precise requirements of measuring the thickness of thermal barrier coatings.