Abstract: A power supply mechanism for a long-stroke seat has a wire harness accommodation box having at least one accommodation space and at least one opening; a drag chain bent and accommodated in the accommodation space, where a first end of the drag chain is relatively fixed to the wire harness accommodation box, and a second end of the drag chain passes through the opening and is slidably disposed in a slideway of a lower slide rail of the seat; a wire harness threaded in the drag chain, where a first end of the wire harness passes through a first end of a wire harness channel and the opening to be connected to a power supply, and a second end of the drag chain passes through a second end of the wire harness channel to be connected to an upper slide rail of the seat.