Antimony nanoparticles, which surfaces were modified by alkyl phenol polyoxyethylene ether, were used as a kind of lubricating additives in liquid paraffin. The tribological properties of antimony nanoparticles as lubricating additives were evaluated and compared with those of pure liquid paraffin on a four-ball test machine. The morphology and chemical composition of worn surface were investigated and analyzed by using SEM and EDS. The results show that the additives can obviously improve the anti-wear and friction reducing properties of liquid paraffin, which are better under high friction load. The double-layer crystal structure of antimony can be separated and glided along cleavage plane by friction-shear force and normal load, respectively. The separating and gliding of antimony can form a physical adsorption film, which can separate friction surface to avoid direct contact of friction surface and play an important role in improving the anti-wear and friction reducing properties.