The utility model provides a UV power supply with water cooling, which involves the field of UV power supply, including the casing. The casing includes an upper cover and a bottom plate, the upper cover and the bottom plate are surrounded by a cavity. The control board and the power board are installed inside the upper cover. The control board is arranged in parallel with the power supply board, and the interior of the floor is installed with a water cooling plate and a cooling plate. The water cooling board is fixed above the heat dissipation plate, and the water cooling board and the heat dissipation plate are fixed on the supporting plate. The IGBT module of the power supply plate is directly connected with one side of the water cooling plate. One side of the heat dissipation plate is equipped with a transformer, the heat dissipation plate is arranged on the other side, and the other side is equipped with a energy storage inductor and a bottom wind. Fan. By setting water cooling plate on the surface of the power supply plate, the utility model uses heat exchange to keep the heat generated by the power device and combine the heat sink with the fan to take away the heat of the transformer, so as to improve the heat dissipation effect and improve the working efficiency and service life of the UV power supply.