A wheelchair is disclosed. Two ends of each of the seat connection tubes are connected with the seat frame and the corresponding side frame, respectively. The seat frame and the seat connection tubes are telescopic by the combination of pressing units and holes. Two ends of each of the front connection tubes are connected with the front tube and the corresponding side frame, respectively. The front tube and the front connection tubes are telescopic by the combination of pressing units and holes. Two ends of each of the rear connection tubes are connected with the rear tube and the corresponding side frame. The rear tube and the rear connection tubes are telescopic by the combination of pressing units and holes. Each back connection tube is connected with the back unit and the corresponding supporting frame. The back unit and the back connection tubes are telescopic by the screwing elements.