The tribological properties of Sb2S3 nano-bundles as an additive in liquid paraffin were evaluated on a four-ball tester, thereafter the performance of Sb2S3 nano-bundles was compared with that of Sb2S3 nano-particles. The comparative analyses of friction coefficients, wear scar diameters and morphology of worn surfaces show that Sb2S3 nano-bundles and nano-particles can both improve tribological properties of base oil, Sb2S3 nano-bundles exhibit better friction reduction and anti-wear properties than Sb2S3 nano-particles at relative low load, and they possess very similar tribological performance at relative high load. As far as the load carrying ability is concerned, the performance of nano-particles is obviously better than nano-bundles. It is inferred that the sliding-rolling friction transition emerges when lubricated with nano-bundles/oil mixture at low load, which contributes to the good lubricating effect of the