Aimed to study the effects of reinforcing or functional fillers on mechanical and tribological properties of PTFE-based friction materials of ultrasonic motor, carbon fibers reinforced PTFE composites modified with different functional fillers with differences in dimension, size, and hardness are fabricated. The tribological performances of PTFE-based friction materials are comparatively investigated under different sliding velocities and normal loads on different surface morphologies, respectively. The experimental results reveal that nano-SiO₂ shows excellent performance in improving friction stabilities and wear resistance in different operating conditions. It is believed the silica-based tribofilms, higher deformation resistance, and bearing capacity play a key role in improving friction stabilities. Furthermore, the results also show that the surface topography plays an important role in wear properties. The lower wear rate (sliding against with the disordered surface) is believed to be attributed to wear debris easy-store characteristic of the topography, which promotes transfer films formation and decreases the wear rate effectively.