This study addresses the temperature-structural coupling challenges in complex-shaped thermal protection components under extreme high-temperature environments. An integrated experimental–numerical approach was proposed to systematically investigate the transient temperature response and structural load-bearing performance of molded resin matrix composites. A negative-curvature strake component was developed and subjected to arc-jet thermal testing under stagnation temperatures exceeding 1500 °C. A high-fidelity thermo-mechanical numerical model was established by incorporating CFD-reconstructed heat flux boundaries. Key findings demonstrate: (1) High consistency between experimental and simulated temperature profiles at critical measurement points, with maximum average percentage error (MAPE) \(\le 9.5\%\) ; (2) No interlaminar delamination or cracking observed in negative-curvature regions under aerodynamic loads, where the maximum thermal deformation at the strake tip was limited to \(0.11\%\) of the total structural length; (3) Structural integrity maintained throughout thermal testing, with peak equivalent stress \(39.8\%\) below the material's allowable strength and residual load-bearing capacity retention exceeding \(60\%\) . The research validates the thermo-structural reliability of molded composites with complex geometries in extreme environments, providing critical experimental evidence for reliability-oriented design of hypersonic thermal protection systems.