A physical analysis and mathematical formulation of the structure of a
n accretion shock wave in the case of young stars are given. Some resu
lts are presented, and the dependence of the structure of the shock on
various parameters is investigated. In the general case, the relative
intensities and profiles of lines in the spectra of T Tauri stars sho
uld depend on the velocity and density of the infalling gas, as well a
s on the accretion geometry. The calculation results may serve as a ba
se for elucidating the nature of the activity of young stars.