Twodimensional (2D) transition metal carbides Ti2C were prepared by etching MAX phase Ti2AlC with ammonium fluoride and hydrochloric acid solution.The structure and morphologies of samples were characterized by Xray diffraction (XRD) and field emission scanning electron microscope (FESEM).Results show that Ti2AlC is etched as Ti2C successfully with ammonium fluoride and hydrochloric acid solution.The tribological properties of the prepared Ti2C nanosheets as an additive in lithium grease were evaluated with a fourball tester and the worn surfaces were analyzed by FESEM and EDS.Results show that Ti2C nanosheets as lubricating additives can obviously improve the friction reducing and antiwear performance of base grease,which has good friction reducing property when its mass fraction is between 01% to 025 %,and has good antiwear property when its mass fraction is 025%.The friction film is formed due to the deposition of Ti2C in the surface of friction,which has good effect on friction reducing and antiwear performance.