Water-soluble nanospheres as lubrication additives have become an important direction in the development of lubrication.Amphiphilic polymer nanospheres P(St-co-SPMA) were prepared by a simple soap-free emulsion polymerization method.The tribological properties of polystyrene(PSt) and P(St-co-SPMA) nanospheres as lubrication additive were investigated on friction and wear tester by changing polymeric monomers,nanosphere content and applied load.The results indicate that the amphiphilic polymer nanospheres with soft/hard-coupled structure can play a very excellent antiwear performance,which can be attributed to the formation of hydration layer on the surface of nanospheres that avoids the direct contact between friction pairs and thus effectively improves the interfacial friction property.PSt and P(St-co-SPMA) nanospheres exhibit better antiwear property under high loads,indicating the high load-bearing capability.This research may lead to new strategies to develop highly efficient aqueous lubrication systems for biological lubrication.