Abstract: A carrier plate applied for a load port is provided, which includes a first guide slot is provided with a first switch to drive a first nozzle to move up and down to switch the position, a second guide slot is provided with a second switch to drive a second nozzle to move up and down to switch the position, a third guide slot is provided with a third switch to drive a third nozzle to move obliquely to switch the position, and a fourth guide slot is provided with a fourth nozzle to move obliquely to switch the position, thereby, the first nozzle, the second nozzle, the third nozzle and the fourth nozzle move to the positions corresponding to the air holes on each of the bottoms of the wafer transfer cassettes to inflate or exhaust the wafer transfer cassette.