Abstract: The effects of different surface treatments of glass fiber on the sliding wear behaviors of PTFE composites were investigated under dry friction conditions. The worn surfaces were analyzed using a scanning electron microscope (SEM). The results show that the friction coefficients and the temperatures of the frictional surface of the polytetrafluoroethylene (PTFE) composites filled with treated glass fiber, under dry friction conditions, are lower than those of the PTFE composite filled with untreated glass fiber, and wear-reducing properties of the PTFE composites with treated glass fiber are better than those of PTFE composite with untreated glass fiber. The PTFE composite, filled with glass fiber treated with rare earths, shows the lowest friction coefficient and temperature of the frictional surface as well as the best wear-reducing properties among the researched composites. The PTFE composite untreated and the PTFE composite treated with the coupling agent are characterized by severe adhesion and transfer. The wear mechanism of the PTFE composite treated with coupling agent and rare earths is characterized by remarkable abrasive wear. The wear of the PTFE composite treated with rare earths is characterized by adhesion, transfer and slight abrasive wear.