Abstract: The fretting wear mechanisms of perfluorinated ethylene propylene copolymer (FEP) were studied on an SRV fretting wear tester with ball on disk point contact and plane contact respectively. It was suggested that ball on disk contact was not suitable for the study of fretting wear behaviors of polymers as the hertzian pressure was much higher than the compression yield strength of polymer and the polymer would be extruded out of the contact regions. In the case of plane contact, on the worn surface of FEP and the transfer film on counterpart metal surface, three regions including wear debris formation region, high stress region, and slightly sliding wear region could be distinguished. The fatigue cracks were produced in subsurface region about 0.5 mm beneath the contact surface of FEP. It was concluded that the fretting wear mechanism of FEP was the combination of surfacial adhesion wear and sub surfacial fretting fatigue.