Aiming at the problem that the imaging system responds unevenly to the light intensity under strong backlight interference, resulting in overexposure of the detected target image, this paper proposes a phase modulation technology to achieve high-resolution imaging of the target in the backlight environment. The light intensity transmission model of the optical system after inserting the phase mask is theoretically deduced. By obtaining the imaging data of the point light source in a variety of mask cameras in the simulation environment, we found that the strong light suppression effect of the cone-shaped mask plate inserted at the aperture diaphragm position of the optical system is much higher than that of the ordinary camera or other masks. We set up a strong light background gradient filter plate imaging physical verification test with an avoidance angle of 0°, compared the response effect of the ordinary camera and the coded camera on the filter plate, and combined it with the gray histogram data of the highlight filter plate imaging, confirmed the theoretical model of light intensity transmission. Therefore, the optical system based on wavefront coding can achieve high-resolution clear imaging of a strong light background.