The main approaches to the development of a reactor unit for the hydro desulfurization of diesel fuels are considered, taking into account the reactivity of the organosulfur components that make up diesel fuel and the formation of pseudocomponents conditionally combining a group of organosulfur components. As the concentration of easily or difficult-to-hydrogenate sulfur-containing components in raw materials increases, the role of a substance limiting the quality of diesel fuel purification may shift from an easily hydrogenated to a difficult-to-hydrogenate pseudocomponent and vice versa. The efficiency of operation of five variants of the reactor unit of hydrotreating plants is compared. It is shown that from the point of view of minimizing the loading of the catalyst, the two-reactor scheme of the hydrotreating process with separate supply of low-boiling and high-boiling fractions of straight-run diesel fuel to the reactors is optimal. The necessity of determining the temperature boundary of their division, taking into account the qualitative and quantitative composition of these fractions by organosulfur substances, is substantiated.