Abstract: Compared with oil-based lubricants, water-based lubricant systems possess excellent cooling and flame-retardant properties, offering great application potential in many fields. However, the highly polar water molecules usually weaken the interactions between water-based lubricant additives and interfaces, thereby hindering the formation of the interfacial adsorption layer and ultimately resulting in poor extreme pressure load-carrying capacity of water-based lubricants. In this study, a polyurea-type ionic liquid was prepared as a water-based lubricant additive. The hydrogen bonding interactions between urea groups enabled the polymer to form a more stable adsorption layer at the interface. The existence of a large number of hydrogen bonds and tribo-chemical films in the polyurea-type ionic liquid was confirmed by multiple characterization technologies (temperature-dependent FTIR, two-dimensional IR, XPS and QCM-D). By comparing the effects of small molecule ionic liquids and polyurea units with different rigidity on the tribological performances of water-based lubricants, it was proved that the synergistic effect of multiple non-covalent interactions (hydrogen bonding, electrostatic interactions and hydrophobic effects) in polyurea ionic liquids could significantly improve the anti-friction, anti-wear performance, and extreme pressure load-carrying capacity of the water-based lubrication system. The final polyurea-based ionic liquid achieved a friction coefficient as low as 0.12 and an extreme pressure capacity up to 1 000 N at polyurea ionic liquids mass fraction of 2%, while the corrosion to metals was significantly reduced.