Aerodynamically heated high temperature dome will produce strong infrared radiation. In some serious cases when the probe reaches saturation, the detecting precision of the seeker for target can be severely affected. In order to reduce the aerodynamic thermal radiation of the dome, a mathematical model of aerodynamic thermal radiation was developed. The aerodynamic heat and the aerodynamic thermal radiation of the hemispherical dome with different thickness were simulated numerically by software of finite element analysis and the mathematical model of aerodynamic thermal radiation. The influence of the thickness of hemispherical dome on the aerodynamic thermal response and aerodynamic heat radiation was analyzed and obtained. Research indicates that in the same flight conditions and in 10 s, when the thickness of hemispherical dome increases from 3 mm to 8 mm, the stagnation point temperature of the dome reduces by 16.41%; the thermal deformation of the dome reduces by 54.2%; the maximum irradiance of receiving surface of the detector decreases by 84.43%. Therefore increasing the thickness of the dome can not only reduce the temperature of the dome, but also effectively reduce the thermal deformation of the dome and the interference radiation illumination received on the detector.