Aiming at the problem that the attenuation of optical power caused by the foggy environment affects the effective communication area between vehicles, considering the size of the car and the two radiation modes of the white light car headlamps, a rectangular channel model of the space vehicle-mounted visible light communication is established. The differential element method is used to obtain the transmission power of the diffuse reflection link, and the integral idea is used to derive the attenuation coefficient of white light in the fog environment and obtain the effective working range of the system.The simulation results show that the power half-angle of the lamp, relative speed, direction of motion, road surface, surface reflective material and position of adjacent lane vehicles vary with degrees of channel attenuation, which affects the reliable transmission of information between vehicles.