The effect of laser treatment on the tribological performance of PEEK under seawater lubrication was studied. The surface morphology and wettability of the laser treated PEEK were analyzed. The relationship between the surface chemical composition and the tribological performance of the laser treated PEEK was discussed. Results show that oxidation occurred during laser treatment with relatively low laser power density, there was no obvious change in surface roughness. Carbonization occurred for the treatment with high laser power density, surface roughness increased significantly, made the surface more hydrophobic. The friction of PEEK under artificial seawater lubrication was reduced after laser treatment. The reduction in friction for the laser treated PEEK under low power density was mainly due to the adsorption of water molecules and cations on the surface of PEEK. For the PEEK treated with high laser power density, solid lubrication due to surface carbonization was the main reason for the reduction of friction and wear.