Abstract: An analysis of the heat transfer characteristics in the airlock module in manned space environmental test shows that air-conditioning in the module is important. A detailed numerical analysis of the air distribution pattern and air-conditioning efficiency in the airlock module is made using the CFD software. And the temperature and airflow field distribution in the module show that the heat accumulation and heat diffusion may be aggravated in a low pressure and it is efficient to adop a two side ventilation pattern to reduce the thermal load in the airlock module. The conclusion of the paper is relevant to related engineering designs.