To evaluate the thermal sealing performance of aerospace vehicle hatch structures, this study proposes a testing method that considers the spacecraft's internal environment. In this approach, the hatch structure specimen is integrated with a pressure-resistant housing to form a sealed cavity, which simulates the spacecraft’s internal environment. This configuration enables simultaneous simulation of aerodynamic heating conditions and pressure differential between the interior and exterior environments. By measuring parameters such as internal air pressure, temperature, and airflow rate within the cavity, the thermal sealing performance of the hatch structure and its impact on the spacecraft’s thermal environment can be systematically assessed. Verification experiments were conducted using typical seal structures, and the results demonstrate that this method provides an accurate and comprehensive evaluation of the thermal sealing performance of aerospace vehicle hatch structures.