Аннотация:The main patterns of the proton precipitation in the atmosphere were described already in the 1970s. The blue-shifted Doppler profiles of hydrogen lines are associated with proton precipitations. It is accepted that these profiles contain information about distribution in the precipitated particle flux. However, some peculiarities of these profiles, namely, the red-shifted wing are not well understood. This red wing is usually explained by large angle scattering at the collision energies less than 1 keV. However, this assumption contradicts with available information about cross sections. Here we analyze the forming of the hydrogen Doppler profile by detailing individual scattering reactions and electronic states. Theoretical estimations are tested by a new version of a transport code modeling penetration of the proton-hydrogen atom flux in the Earth’s atmosphere. The Monte-Carlo method with a collision-by-collision algorithm has been used. The results have been compared with available observations.