This study reveals the synergetic enhancement of oxygen plasma treatment on the interfacial properties and impact resistant of ultrahigh molecular weight polyethylene (UHMWPE) fiber-reinforced polymer matrix composites (PMCs). The UHMWPE fiber reinforcement was modified by oxygen plasma with different parameters including input power, treatment time and gas flow rate . Then, the surface physicochemical properties of modified fibers were analyzed. Oxygen plasma modified UHMWPE/vinyl ester composites exhibited an enhanced interface shear performance of 90.99%, which would significantly influence the mechanical properties of the composites. The optimal parameters were proved to be an input power range of 150–180 W, a time range of 120–150 s, and a gas flow rate of 8sccm, at which situation the tensile strength had been enhanced 10.67%, the impact-resistant damage projection area and dent depth had been reduced up to 51.93% and 24%, respectively. Simultaneously, the energy dissipation pattern dominated by fiber fracture was gradually formed in the modified composites, which maximize exploitation of the fiber-reinforcing effect and improved the impact resistance.