Abstract: The control rudder is a key component for controlling the attitude of hypersonic aircraft, but the gap area of the rudder is prone to serious thermal load problems. This study adopted a novel control method for preventing aerodynamic heat, and through numerical simulation, the distribution law of aerodynamic heat in the gap and the control effect of thermal protection were investigated. When the angle of attack changes, the heat flux on the windward side of the rudder and the rudder shaft will increase significantly. Therefore, this study attempted an active flow control method by introducing jets at different positions inside the gap. The results show that adding a jet to the bottom plate inside the gap can effectively block high-temperature airflow from entering the gap. It can generate a thin film effect near the rudder shaft, reducing the heat flux on the surface of the rudder shaft. The thermal protection effect is significant as the distance between the jet port and the rudder shaft decreases. But in the case of angle of attack, it is necessary to adjust the jet angle and position according to the incoming flow direction to achieve the best effect.