Abstract: This paper analyzes the International Space Station (ISS) Columbus system level environment control system (ECS) test, which was directly carried out in the integration hall with the normal atmosphere pressure instead of in the large vacuum chamber or with the external heat flux simulators such as the solar simulator or the infrared lamp. This test simulation cases include the launch, normal and failure operation modes, and are used to validate the integrated overall thermal mathematical model (IOTMM) and the interrelationship between the active thermal control system (ATCS) and the environment control and life support system (ECLS).