With nano-WS2 and nano-TiN as additives,the effect of nanomaterials with different concentrations on the friction reducing and antiwear properties of lubricants was studied.The experimental results show that,after adding nanomaterials,the friction reducing and antiwear properties of the lubricating oil are improved obviously,and the wear types are changed significantly,among them,the wear type after adding nano-TiN is changed from abrasive wear to adhesive wear,and the wear type after adding nano-WS2 is changed to coexistence of adhesive wear and abrasive wear.With the increase of the mass fraction of nanoparticles,the friction reducing and antiwear properties of lubricating oil is first increased and then decreased.Among them,nano-TiN with 03% mass fraction has the best friction reducing and antiwear effect.Compared with base oil,the friction coefficient can be reduced by from 5% to 8% and the wear scar diameter can be reduced by from 26% to 32%.