The stability of calibrating thermocouples with a dry block calibrator is crucial for the reliability of measurement results. It is found that the power supply stability of the dry block calibrator will affect its heating stability and further affect the calibration result. Therefore, a stable and reliable power supply device should be used. The performance of the temperature control system of the dry block calibrator is also related to the calibration stability. If the temperature control system is unstable, the temperature will fluctuate. In addition, the aging degree of the thermocouple will also affect the stability. Aged thermocouples may have phenomena such as measurement value drift. By regularly replacing aged thermocouples, optimizing the temperature control system of the dry block calibrator, and ensuring power supply stability, the stability of calibrating thermocouples with the dry block calibrator can be improved.