| 77 GHz millimeter-wave radar has broad application prospects in the field of unmanned vehicles due to its small size and high resolution. As an important part of the millimeter wave radar system, radome can protect radar working state from the harsh environment. However, the radome will introduce a medium on the propagation path of the radar electromagnetic wave, which will cause the antenna radiation performance to be attenuated. In order to improve the influence of the radome on the radiation performance of the radar antenna, this paper proposes an optimal design method for radome based on 77 GHz millimeter-wave corner radar. The optimization method uses the genetic algorithm (GA) as the optimization algorithm ,and uses MATLAB to combine the GA and the high-frequency simulation software HFSS. The method optimizes the arc central angle of the arched radome cross section and the vertical distance between radome and antenna, so that the radar antenna has high gain and low side lobes in its working frequency band, and increases the 3 dB azimuth beamwidth to increase the width of the field of view of millimeter-wave corner radar. The simulation results show that the 3 dB azimuth beamwidth of the array antenna with the optimized radome is increased by 37°, the working bandwidth is increased by 1.04 GHz, and the maximum side lobe in the elevation plane is reduced by 1.02 dB. The results show that the radome designed based on the proposed optimization method can effectively increase the field of view of the millimeter-wave corner radar array antenna, widen the working frequency band of the radar antenna array, and reduce the elevation maximum side lobes. The mechanical properties analysis shows that under typical working conditions, the radome is not damaged in the process of falling from the surface or the edge, and no instability occurs, which meets the requirements of strength, stiffness and stability. A numerical example of 77GHz millimeter-wave corner radome verifies the effectiveness of the optimization method.