An apparatus for making high-oxygenated water includes an oxygen supply, an exchange tank, and a pressure tank. The oxygen supply respectively supplies pure oxygen to the exchange tank and the pressure tank. The pure oxygen is dissolved in water in the exchange tank in a normal pressure environment to obtain oxygenated water. A slow-down unit is provided in the exchange tank to extend the time of the pure oxygen staying in the exchange to raise the dissolved oxygen of the oxygenated water. Next, the oxygenated water is drained to the pressure tank, and then the pure oxygen is dissolved in the oxygenated water in the exchange tank in a high pressure environment to obtain high-oxygenated water.