The increasing speed of high Mach number aircraft brings about significant aerodynamic heat problems. The specific heat mutation of supercritical fluid near the Witton line and the good stagnation heat transfer effect of jet impact provide a solution to this problem. This study of high Mach number aircraft stagnation simplified set the supercritical CO2 concave jet impingement numerical model, and the reliability of the numerical model was verified. The jet impingement heat transfer characteristics of SCO2 under a wide heat flux range (0.7~6.5 MW/m2) and different inlet pressures (7.5 MPa, 8.5 MPa, 9.5 MPa) were studied, and the differences between concave cooling and plate cooling were further compared and analyzed. It was found that the SCO2 jet impingement cooling effect was slightly better than air and nitrogen, but the required coolant storage space was only 1/9 of the latter two, and the structure was more compact. When the inlet temperature was lower than the pseudo-critical temperature, the heat transfer coefficient increased with the increase of the inlet pressure, and the maximum increase was 24.7%. When the wall heat flux was lower than 5 MW/m2, the overall temperature of the solid surface was 500 °C lower than the melting point of tungsten, a commonly used material for the aircraft’s stationary shell, indicating that SCO2 jet impingement can play a cooling and protection role on the hypersonic vehicle’s leading edge. In addition, compared with plate cooling, concave surface will increase the uneven temperature and lower thermal performance of the cooling surface. The difference between the two also indicates the necessity of research on concave jet impingement, which was helpful to provide more references for the design of the SCO2 jet impingement technology in the stagnation active cooling system of high Mach aircraft.