Abstract: Bi-Pb-Sn-Cd nanoalloy particles were prepared using sonochemical dispersion method. The morphology, size, and phase composition of the nanoparticles were analyzed by means of X-ray diffraction, differential thermal analysis and thermogravimetric analysis (DTA-TG), and transmission electron microscopy (TEM). The tribological properties of the nanoparticles as an additve in liquid paraffin were evaluated using a four-ball test rig, while the worn steel surface was observed using a scanning electron microscope. It was found that the as-prepared nanoalloy particles had good dispersing ability and composed of spherical crystallines with a size of 10~20 nm. The nanoparticles as the additive in liquid paraffin showed good friction-reducing and antiwear abilities and hence could be used as a good lubricating oil additive.