The paper proposes an approach to increasing the efficiency of plasma modification of the metal product surface layer based on the study of the effect of pressure in the working chamber of a technological unit on its course and outcomes. It was found that there is such influence, and it is manifested in a heat flow direction change and leads to the intensification of either heat conduction (with increasing pressure), or heat transfer and radiation from the surface (with decreasing pressure). In the first case this leads to the formation of the most compacted composite structure in the surface layer, and to the transition layer formation between the structure and the main material of the product. In the second case the compaction of the surface layer is minimal, no transition layer is formed. The pressure change effect mechanism associated with the violation of the dynamic equilibrium between adsorbed and desorbed particles on the product surface when changing the temperature regime has been identified. It is shown that after switching off the plasma, it is necessary to control the heat flow propagation, and that the course of the lag temperature curve can serve as an operational indicator of the control quality.