The invention discloses a multiplex composting and ventilating system and a ventilating method and application thereof. The invention provides the multiplex composting and ventilating system aiming at the defects that both the prior composting control system and the prior composting method require configuration of a stockpile body and a set of complete ventilating devices comprising a fan, thereby having large investment, large energy consumption and the like. A central control instrument of the system can control a fan and a plurality of electric air valves to ventilate a plurality of stockpiles requiring ventilation. The invention also provides the composting and ventilating method utilizing the multiplex composting and ventilating system. The method realizes alternate and intermittent ventilation on various stockpiles in the system by starting the stockpile electric air valves of the system and adopting a dynamic queuing mechanism. The ventilating system and the ventilating method can greatly reduce the equipment investment of construction of a stock dump, and reduce maintenance cost and energy consumption during operation.