Mechanical wear accounts for one third of present global energy consumption. However, it still lacks an efficient lubricant to simultaneously achieve a highly efficient lubrication and metal wear repair. Herein, we report that carbon quantum dots (CQDs)/CuSx nanocomposites show enhanced lubrication and metal wear surface repair abilities when used as additives. The highly efficient lubrication and metal wear repair properties should be attributed to the combination of the multi-layer graphite structure of CQDs and the high chemical activity of CuSx nanoparticles.