The invention discloses a water cooled power supply device suitable for an open water source. A power source circuit module is arranged in a power source box, and a water-cooled base is arranged outside the box. Water of the open water source is circulated between the water-cooled base and the open water source in cooperation with the input medium and the output medium. Heat generated by the power circuit module in the box is taken away via circulation, and therefore effective water cooling effects are exerted. Besides, the power source circuit module is arranged in the power source box so as to ensure that the power source circuit module is not damaged and can operate normally; the service life of the whole device is improved and added value of products can be increased.