Study on mutiple-unit ventilating flow field of main building (turbine hall) in thermal power plant adopting air coolers has been carried out by using computational fluid dymamics. Results show that the natural ventilation of the main building was destroyed in the case of air cooler being 12m apart from the mzin building

ventilating and cooling all do not satisfy the requirements of specifications

and mechanical ventilation has to be asisted. Results of calculation indicate that the multiple-unit ventilation made of combining natural inlet air with mechnical exhaust air

or combining mechanical inlet air with natural exhaust air

can be used for the main building respe-tively

to satisfy the requirements of ventilating and coolingdown specified in design.