Triboelectric nanogenerator (TENG) is a prospective energy harvesting technology, especially polymer-based TENG has achieved remarkable achievements. However, most polymer-based triboelectric layers suffer serious structural degradation and rapid decrease of charge density at high temperatures, which severely lowers the power supply capacity of TENG and definitely limits their applications in extreme environments. Herein, the antioxidants are introduced into liquid crystalline polyarylate (LCP) to fabricate thermally stable TENG and enhance its thermal oxidation resistance. The peak voltage of the resultant TENG is boosted to 73.6 V at 200 °C, which is 144.1% higher than the value at 25 °C, indicating the remarkably high-temperature enhancing effect on electrical output performance. Meanwhile, the high-temperature enhancing TENG (HTE-TENG) exhibited a peak output electrical power density of 1071.3 mW·m−2 under a 109 Ω load. This work provides a sustainable route for reliable energy devices and electronics to serve in potential applications, such as rescue work, personal protection, and extreme environments.