Aiming at the problems of the distortion of the pattern, wave transmission rate degradation, excessive aiming error and cross-polarization level lift when electromagnetic wave passed through the dielectric radome, a novel airborne radome based on variable thickness design was proposed. Firstly, the overall structure of the antenna-radome system is determined, and after analyzing the incident angle of electromagnetic waves through the radome, the optimization method of variable thickness design is adopted to reduce the incident phase difference and improve the transmission efficiency of electromagnetic waves, and finally the performance parameters of the variable thickness radome are analyzed by 3-D ray-tracing method (combined with the aperture integration method). The simulation results show that the transmittance is more than 90% in the 7-13GHz range, and the effect of radome on antenna pattern, VSWR and cross-polarization level lift can be significantly reduced by the variable thickness design of radome core layer.