This work was to reveal magnetic response to wear-resistance of polyetheretherketone/Cu nanowires composites under water lubrication condition. The tribological performance, the worn surfaces, especially the tribofilms' nanostructures and nanomechanical properties with and without magnetic field were investigated. The results reveal that magnetic field can enhance materials transfer, quicken tribofilm formation, and alleviate the stress concentration of the tribofilm. And magnetic field improves the structures and properties of the tribofilm, endowing which with superior easy-to-shear character and wear-resistance ability. Moreover, magnetic field keeps an ordering molecular structure of the PEEK matrix when transformed onto the worn surface, making up the friction heat loss due to the absorption of the running water, and further promoting the tribo-chemical reaction and the tribofilm formation.