Abstract: Searching for a good lubricant to minimum wear and tear of mechanical parts is a research hotspot for domestic and foreign scholars.Nanofluids,formed with base oil and nanomaterials exhibits better tribological properties compared to conventional oils.The preparation methods of nanofluids,including single-step method and two-step method,and their advantages and disadvantages are introduced,the effects of the different nanoparticle additives on the tribological properties of base oil are reviewed and the follow-up study of nanofluids is pointed out.