The invention discloses a curtain wall system which comprises a keel, a pressing plate and a curtain wall plate clamped between the keel and the pressing plate. A carrier table is arranged between the keel and the pressing plate, one end of the carrier table is fixedly connected with the keel, and the other end of the carrier table is connected with the pressing plate through a fastener in a fastening mode. A heat insulation gasket is arranged between the fastener and the carrier table, and a make-up piece which moves downwards under the action of the gravity of the curtain wall plate and makes up the gap between the fastener and the carrier table when the heat insulation gasket loses efficacy and disappears is arranged between the heat insulation gasket and the carrier table. The curtain wall system has the advantages of being simple in structure, convenient to install, and capable of achieving seconary fastening.