The invention discloses a variable adjustment backswept wing mechanism of a fixed-wing aircraft. The variable adjustment backswept wing mechanism comprises a wing, a wing pull sheet, a pull sheet sliding frame, a wing pull rod, a pull rod fixing seat and a guide seat, wherein an end part of the outer side of the wing pull sheet is fixedly connected with the wing; an end part of the inner side of the wing pull sheet is hinged with a pull sheet sliding block and the wing pull rod; the pull sheet sliding frame is fixed on an aircraft body; a pull sheet sliding rail slot which is in sliding fit with the pull sheet sliding block is formed in the pull sheet sliding frame; the other end of the wing pull rod is hinged with the pull rod fixing seat; a screw rod is mounted in the guide seat; the pull rod fixing seat is mounted on the screw rod in a sleeving manner and is connected with the guide seat in a sliding manner; a driving end of the screw rod is connected with a driving motor through atransmission mechanism. The variable adjustment backswept wing mechanism of the fixed-wing aircraft is reasonable in structural design; a backswept wing can reasonably change according to a flying requirement, so that a better flying speed can be provided for flying of the aircraft.