Accurate positioning of measuring ends of thermocouples has an important influence on the calibration and use of thermocouples, especially for armored noble metal thermocouples. It is impossible to accurately identify the position of thermocouple measuring ends inside protection tubes by visual inspection, and therefore the top of protection tubes is chosen as the position for measuring ends in the calibration and use processes of thermocouples. However, through field test, the measuring ends of armored noble metal thermocouples are not located at the top of protection tubes. This paper provides a method for accurate positioning of armored noble metal thermocouple measuring ends.