The phenomenon of surface injection is widely present in the active and passive thermal protection systems of high-speed aircraft. Clarifying the impact of this effect on the aerodynamic heating environment is of great significance in the design of efficient thermal protection systems for aircraft. In response to this issue, a numerical calculation method for aerodynamic heating environment under surface injection conditions has been developed, and numerical simulation studies have been conducted on the impact of the magnitude and spatial distribution of mass flow rate of injection gas on aerodynamic heating environment under high-speed inflow. The results indicate that surface injection will alter the velocity and temperature fields near the wall, as well as the synergistic relationship between the two fields, leading to weakened heat transfer. The larger the mass flow rate of the injected gas, the more significant the heat reduction effect. When the total mass flow rate is the same, the spatial distribution of the mass flow rate of the injected gas will affect the wall cooling effect.