We determined the tensile properties of 2D-C/SiC composites at temperatures up to 1873 K with a wide range of loading rates (10−3 s−1 and 400 s−1) in argon and air. We developed a high-temperature Hopkinson tensile bar with tensile strength based on the loading rate, temperature, and oxidation. Under high loading rates, tensile strength was influenced by the nucleation of multiple cracks and the improvement of C-fiber pull-out length and interface strength. In argon, material component performance and thermal residual stress influenced the 2D-C/SiC high-temperature tensile properties. In air, oxidation damage significantly affected the tensile properties of 2D-C/SiC regardless of loading rate or temperature. This led to lower tensile strength and higher strain rate sensitivity. Our observations can enhance the understanding of the failure mechanism of thermo-chemo-mechanical coupling in 2D-C/SiCs and will provide guidance for safe application in extremely high-temperature conditions.