Abstract: Compared with the conventional cooling tower on the ground, the air duct built-in cooling tower has advantages of small volume, less occupancy, lower impact on landscape, lower noise, less impact on hygiene safety. Taking the air duct built-tin cooling tower in a station in Beijing as an example, the technical requirements, pipe network characteristics and key points of machine room design of the air duct built-in cooling tower in metro station are expounded, and the problems existing in the new cooling system composed of the air duct built-in cooling tower are analyzed. Specific technical measures to ensure the high-efficiency refrigeration effect of the cooling tower and the stable operation of the cooling system are put forward, providing technical space for the innovative application of air duct built-in cooling tower.