Floating isle positioning device

The invention discloses a floating isle positioning device used for fixing a floating isle to a revetment and allowing the floating isle to adjust in height with water level. The positioning device comprises a vertical guide rail. Two ends of the guide rail are fixed to the revetment. The side of the floating isle is provided with a sliding device which is disposed on the guide rail in a sleeving manner. In a river channel the positioning device is vertically placed; the height of the floating isle can change with the water level by the aid of the vertical guide.