Atmospheric polarization mode is an important basis for the study of polarized light navigation. Most of the previous studies have taken a macroscopic perspective and regarded the atmospheric polarization mode as an external light field on Earth. Based on the Rayleigh scattering at a single particle, this paper considers the polarization of sunlight during the propagation of sunlight in the atmosphere. Under the condition that the approximation of sunlight is regarded as parallel light, the polarization of light at different observation positions is predicted by analyzing the relationship between the position of observation points on the ground and the visual position of the sun, so as to establish an atmospheric polarization model. Explaining the atmospheric polarization mode from a microscopic perspective can provide a basis for the study of large-scale particle scattering polarization patterns. At the same time, it provides a theoretical basis for multi-sensor cooperative orientation.