Due to the long time constants and poor dynamic characteristics of armored thermocouples, dynamic errors occur in dynamic tests, which often do not meet the actual measurement requirements. A dynamic compensation model design method based on Harris Hawk Optimization Algorithm (HHO) is proposed, and using this compensation model, the dynamic characteristics of the armored thermocouple are improved. The dynamic calibration experimental data of the armored thermocouple is obtained by using the experimental system based on the high-temperature calibration furnace, and the parameters of the dynamic compensation model are optimally selected using the HHO to complete the model design. The experiments show that the time constant of armored thermocouple can be reduced from 37.33s to 1.91s by this test system and method, which can be used to improve the dynamic characteristics of thermocouple sensor, extend its service life and reduce the cost in some specific working environment.