Abstract: The single crystal silicon wafer was implanted by carbon ion with different implantation doses.The changes of hardness and elastic modulus of silicon implanted by carbon ion were studied on the in-situ nano-mechanical testing system.The sliding tests on silicon wafer and the C+-implanted silicon wafer were performed on the UMT-2 Tribometer.The morphology of worn surface was observed with the S-3 000 N Scanning Electron Microscope.The nano-hardness and elastic modulus increase for the C+-implanted silicon wafer.Friction-reducing effect of the C+-implanted silicon wafer improve and its friction coefficient decrease to a great extent.Wear mechanisms of the single crystal silicon and silicon implanted by carbon ion are similar.