MoS2-Cr3O4 composite films were prepared by the combination method of PVD and liquid phase synthesis. The microstructure and tribological properties of films have been investigated. The results indicate that the size of Cr3O4 varied from 5 nm to 500 nm and the shape of Cr3O4 changed from nanospheres to nanorods by adjusting concentration of CrCl3. The MoS2-Cr3O4 composite films developed excellent wear resistance and much lower friction coefficient than sputtered MoS2 both in vacuum and 45%RH air. During friction, the Cr3O4@MoS2 core-shell structure with Cr3O4 core of high hardness and soft MoS2 shells were formed and played the role of nanobearing, which reduced the friction and wear of the composite film. Besides, better oxidation resistance and tribological property of the MoS2-Cr3O4 composite films in humid air were attributed to the Cr3O4 nanoparticles, which occupied the most of dangling bond sites.