Provided is a floating rotation gyro on water. The outer surface of a buoyancy housing is provided with sprinkler heads. The upper surface of the buoyancy housing is provided with a color illuminator. An upper magnet and a lower magnet are fixed out of a pump water housing. The lower end of the pump water housing is fixed in the buoyancy housing. A water outlet valve is fixed in a center hole of the pump water housing. The pump water housing is internally provided with an iron core piston. A sealing cap seals a water inlet channel of a water inlet cavity, and a ball sealer seals the water inlet channel of an extrusion cavity. A spacing hole on the upper end of the iron core piston is fixedly provided with a water diversion limiting board. An inner cone hole of the iron core piston is internally provided with the ball sealer. The lower end of the iron core piston is provided with a holding hole. The floating rotation gyro on water is compact in structure and beautiful in appearance, and is an entertainment tool when people are in leisure, and a tool for children to play. When the gyro rotates on a water surface, the gyro has ornamental value and entertainment value.