A recuperator is a key component and plays an important role in the high-temperature gas-cooled reactor combined with gas turbine (HTGR-GT) system. A distributed parameter model was proposed to study the dynamic characteristics of the recuperator of the HTGR-GT cycle, and this model was solved using an implicit arithmetic. Basic characteristics of the recuperator were analyzed using responses of the recuperator to step disturbances of temperature and mass flow. The response of the recuperator to the temperature disturbances has two different characteristic times 1 and 2 depending on the relation between the response and the disturbance. The response of the recuperator to mass flow disturbance has a characteristic time 4 that is between 1 and 2. An example of coupled disturbance of temperature and mass flow was simulated by the distributed parameter model. This example shows the influence of the three characteristic times to the dynamic characteristics of the recuperator. When the system power of HTGR-GT is regulated slowly, the core temperature distribution of the recuperator hardly varies. However, when the electric load of the system is rejected from full power, the core temperature, especially in the front of the recuperator, suffers from a drastic change in temperature.