g-C3N4 has a strong C-N covalent bond within the monolayer and a weak van der Waals force between the lamels, which enables it to have similar lubrication properties to other two-dimensional layered materials. In this study, a new type of g-C3N4/MoS2/ZnS heterogeneous nanocomposites was prepared by a one-step hydrothermal method XRD, SEM, FI-IR, and other methods were used to systematically study it. Furthermore, a ball-on-disk tribometer extensively examined the tribological behavior of g-C3N4/MoS2/ZnS heterojunction in pure oil. The relationship between applied load and rotational speed on performance is also revealed. Compared with g-C3N4 and g-C3N4/MoS2 nanocomposites, g-C3N4/MoS2/ZnS has better frictional properties. It is worth noting that when g-C3N4/MoS2/ZnS is in the base oil mass ratio at 1.0 wt.%, the friction coefficient is reduced by 49%. In addition, g-C3N4/MoS2/ZnS ternary heterojunction exhibits better tribological properties than g-C3N4/MoS2/ZnS mixture, expanding their practical applications in industry and agriculture.