The aim of this work is to evaluate the effects of oxidation treatment and the addition of silicon dioxide (SiO₂) on the mechanical properties of carbon nanotube (CNT)/polytetrafluoroethylene (PTFE) composite film. A powder impregnation process with integrated inline continuous oxidation of CNTs was used to produce CNT/PTFE composite. CNT/PTFE composite was processed into test laminates by compression molding, and interface-dominated composite properties were studied. The tensile strength of composites-containing SiO₂ and oxidation-treated CNT improved obviously.