A sliding seat, being manufactured either together with a wheelchair as a component or separately as an accessory to a used wheelchair and aiming at helping a wheelchair occupant enter into or exit from a motor vehicle, comprises a supporting rack, a siding cushion, and an extender. The supporting rack has a top-board, a bottom frame, and a hoisting device in between. On the upward surface of the top-board, there are two crosswise sliding rulers. The sliding cushion has a soft cushion top and a solid baseboard which has two sliding sleeves on its downward surface to sheathe the sliding rulers of the top-board of the supporting rack. The extender also has two crosswise sliding rulers, which can connect with or disconnect from the sliding rulers of the top-board of the supporting rack. When being connected, the extender extends the two elongated sliding rulers into an open-door motor vehicle and lays them on the vehicle seat. Then, on the elongated sliding rulers, the sliding cushion and the wheelchair occupant on it can slide from the supporting rack into the vehicle and sit on the vehicle seat, or from the vehicle seat back onto the supporting rack.
