Abstract: In this paper, PTFE and Al₂O₃/PTFE composites were prepared by cold pressing and hot sintering technology. DSC characterization was performed to evaluate their thermal stability and the result showed that due to the high inert of Al₂O₃, the crystal structure of PTFE was not changed and little effect on the thermal properties of PTFE was observed. Moreover, the tribological properties of PTFE and Al₂O₃/PTFE composites in temperature range from -100 to 100 ℃ were studied, and micro/nano tribological performance of PTFE and Al₂O₃/PTFE were compared at room temperature. Tribological results showed that the lowest friction coefficient of PTFE was 0.15 at 100 ℃, while its lowest wear rate was 1.0×10⁻⁶ mm³/(N·m) at -100 ℃. After 25 ℃, the wear rate increased sharply and reached the maximum value of 1.0×10⁻³ mm³/(N·m) at 50 ℃. With the increasing of temperature, the interlaminar energy of PTFE increased, which made it easier to produce creep by sliding shear, so that the friction coefficient of PTFE decreased and the wear rate increased gradually. The incorporation of Al₂O₃ significantly affected the tribological behavior of PTFE. Above 25 ℃, the friction coefficient of Al₂O₃/PTFE was higher than that of PTFE, while the wear rate was lower than that of PTFE. The friction coefficient of Al₂O₃/PTFE reached the maximum value of 0.51 at −50 ℃, and then decreased gradually with the increase of temperature, and reached the minimum value of 0.22 at 100 ℃. It was assumed that PTFE was frozen at −100 ℃ and a small amount of Al₂O₃ was released to act as lubricant, which made the friction coefficient of Al₂O₃/PTFE lower than that of PTFE. With the increase of temperature, more and more Al₂O₃ nanoparticles were released, and the aggregation of large particles was not conducive to the lubrication, so the friction coefficient was larger than that of pure PTFE. With regard to the wear rate, the lowest of wear rate Al₂O₃/PTFE was observed at −100 ℃ and the highest was obtained at 50 ℃. As the temperature increased, PTFE began to creep, due to the mechanical enhancement of Al₂O₃, the wear rate of Al₂O₃/PTFE was always lower than that of PTFE. Micro/nano mechanical properties and tribological properties showed that the creep characteristics of PTFE made its micro friction coefficient lower than Al₂O₃/PTFE. Additionally, Al₂O₃ enhanced the hardness of PTFE, which endowed high load carrying capability with Al₂O₃/PTFE and improved its abrasiveness. The worn morphologies of PTFE and Al₂O₃/PTFE were characterized to compare their wear mechanism. At low temperature, the wear debris of PTFE remained frozen, which resulted in abrasive wear. The increasing temperature led to the creep of the materials, abrasive wear gradually transited adhesive wear. However, the addition of Al₂O₃ enhanced the strength of the polymer matrix, and the wear rate was greatly reduced compared with pure PTFE. EDS showed that the agglomeration occurred to Al₂O₃/PTFE at the rubbing interface, which also confirmed the occurrence of abrasive wear of Al₂O₃/PTFE. The tribological mechanism revealed that the tribo-film formed on counterpart surface during sliding process was the key factor determining the friction behavior. XPS analysis showed that more Al₂O₃ particles were released due to the aggravated creep behavior of PTFE molecular at high temperature. The Al₂O₃ had high hardness and strength, which endowed the tribofilm with high load carrying capability, leading to the distinctly different tribological performance between PTFE and Al₂O₃/PTFE. In addition, the reaction between PTFE and counterpart was apt to happen induced by friction heat, which can improve the bond between the tribofilm and the counterpart. This is of great significance for the design of polymer composites under extreme conditions.