Abstract: As one of the active thermal protection technologies, transpiration cooling is expected to meet the design requirements of the thermal protection system for new high speed vehicles. In order to meet the needs of the future active thermal protection design for transpiration cooling research methods and the study of mass ejecting flow field interference, porous material gas ejecting method is used to simulate the flow field interference effect caused by the ejecting of transpiration cooling gas from the wall into the boundary layer, with a high-precision mass flow controller providing accurate control over the gas mass flow rate. ln this way a simulation method for transpiration cooling test of gas working medium in the shock tunnel is developed. Based on the self-developed aerodynamic physical flow field calculation software (AEROPH_Flow), the numerical simulation calculation method of gas ejecting in high-speed flow field is developed by constructing the boundary conditions of wall mass ejecting. The heat reduction effect of gas injection was measured in the FD–14 shock tunnel of China Aerodynamics Research and Development Center. The Mach numbers of the wind tunnel were 8 and 10, the Reynolds numbers were 4.3 × 10⁶, 4.0 × 10⁷ and 4.4 × 10⁶ m^–1, the angles of attack were 0° and 10°, and the mass flow rates of gas injection per unit area were 10 ～ 160 g/(m²·s). Numerical simulation was carried out under the same conditions. The results of the wind tunnel test show that the ejecting gas has a cooling effect on the wall surface. The decrease of the angle of attack, the increase of the flow rate and the increase of the Mach number lead to the increase of the cooling effect on the wall surface under the conditions of different incoming flow and different mass flow rates of the ejecting gas. The typical wall heat flux test results under the conditions of laminar/turbulent/transitional flow in the downstream of the ejecting region were obtained by wind tunnel tests. The existence of ejecting gas makes the laminar boundary layer heat flux in the downstream of the ejecting region decrease obviously, while the turbulent boundary layer heat flux does not change obviously. The transition position of the boundary layer advances and the heat flux increases 3 ～ 4 times. The numerical simulation results are in good agreement with the wind tunnel test results, and the wall heat flux contrast deviation is less than 20%. Due to the coupling effect of ejecting gas interference and boundary layer transition, the wall heat flux in the downstream of ejecting region continuously rises along the flow direction in wind tunnel tests, so it is impossible to determine the precise boundary layer transition position. According to the numerical simulation results under laminar condition, the heat flux climbing effect caused by boundary layer transition can be stripped away, which can help to determine the boundary layer transition position in the downstream of ejecting region in wind tunnel tests.