Low-dimensional fillers play an important role in improving the tribological properties of poly(tetrafluoroethylene) (PTFE) composites. However, the reinforcement mechanism is not fully understood, since few in situ experiments are able to capture the dynamics evolution and interfacial behavior of fillers. Herein, the tribological behavior of PTFE composites filled with graphene (Gr) sheets and carbon nanotubes (CNT) at the nanoscale is investigated. The results demonstrate that the composites filled with the CNT and Gr fillers have much better wear resistance than that of the pure PTFE, and the wear amounts are reduced by 76.2% and 85.7%, respectively. The relative bond and angle energy of PTFE indicate less deformation in the reinforced composite matrices. The calculations of interfacial interaction energy and radial distribution function reveal that the Gr fillers have better reinforcements than CNT due to stronger interactions at the Gr/PTFE interfaces.