An underwater light includes a hollow aluminum outer casing, a hollow sealing cover, and a screw bolt. The sealing cover is coupled with a head connector of a water inlet pipe via the screw bolt. A light base is provided between the sealing cover and the screw bolt. An annular transparent light cover is installed inside the aluminum outer casing. A circuit board with diode embedded is mounted within the transparent light cover. In addition, a fastener is coupled at the internal top portion of the hollow sealing cover, and the screw end of said fastener is coupled with a nut defined as a nut so as to affix a water outlet. A waterproof connector head is coupled with the internal bottom portion of the hollow sealing cover and a wire hole is provided within the hollow sealing cover.