The embodiment of the invention discloses a transmission device for opening and closing a ventilation plate of a unit curtain wall. The transmission device comprises a rotating assembly, a transmission mechanism, a baffle and the unit curtain wall. The ventilation plate is embedded in a main body structure, and a plurality of ventilation holes are formed in the ventilation plate. When a cover plate and the main body structure are in a gradually buckled state, a pressing plate applies certain pressure to a shifting plate, so that one end of the shifting plate is pressed downwards, the other endof the shifting plate is lifted, the other end of the shifting plate abuts against the baffle, and the baffle can be attached to the ventilation plate. Due to the fact that the plurality of ventilation holes are formed in the ventilation plate, and meanwhile the ventilation holes are blocked, the effect of blocking air circulation is achieved. When the cover plate is gradually lifted, along withthe lifting of the cover plate, the other end, which initially abuts against the baffle, of the shifting plate changes to be separated from the baffle, the baffle is separated from the ventilation plate, the ventilation holes are opened, and air exchange circulation is realized. Operation is easy, installation is convenient, the cost is saved, the state is stable, and the normal working function of the ventilation holes and the heat preservation and insulation performance are guaranteed.