In order to improve the friction and wear properties and filmforming properties of low viscosity lubricating oil,nano-TiO2 was chosen as additive,low viscosity polyalphaolefins (PAO8,PAO10) and polyether (PAG) were chosen as base oils.The effect of nano-TiO2 additive on the friction and wear properties of lubricating oil was investigated on a fourball friction and wear test machine,and the influence of various speed and load and the mass fraction of nano-TiO2 on the filmforming performance of lubricants were investigated through interferometry elastohydrodynamic rig.The results show that the addition of a certain mass fraction of nano-TiO2 additives can significantly improve the antiwear and friction reducing properties of lubricating oils.PAO8,PAG and PAO10 base oils show the smallest friction coefficient and wear scar diameter by adding mass fraction of 0.3%,0.05% and 0.3% of TiO2,respectively.By comprehensively comparing the friction coefficient and wear scar diameter,nano-TiO2 shows better antiwear and friction reducing performance in PAO8 base oil,which can reduce the friction coefficient by about 54.5% and the wear scar diameter by about 10.4%.As the entrainment speed increases,the minimum film thickness of the lubricating oil gradually increases,and at the same entrainment speed,the minimum film thickness with a certain mass fraction of nano-TiO2 additive increases significantly compared with pure base oil.With the increase of the mass fraction of nano-TiO2 particles,the minimum film thickness increases,indicating that the addition of nano-TiO2 can improve the filmforming properties of lubricating oil.