Abstract: The invention is related to an improved water tank with an ultraviolet sterilization lamp. It is especially to make water directly contact the sterilization lamp during sterilization. Inside the lamp, there is no air accumulation. The improved water tank with an ultraviolet ray sterilization lamp is characterized as effective and optimal in sterilization effect with prolonged time period for sterilization. The improvement characteristics include a water inlet and an outlet, which are respectively equipped at the inner sides of the front and the rear joint connected to the inner side of a tube at the tangent location. A spiral strip is set at the externals of the sterilization lamp. Both ends of the sterilization lamp are equipped with fixture rings, which are internally laid with O-shaped rubber rings and are locked by tightening rings to firmly fasten both ends of the sterilization lamp at the external end of the front joint and the rear joint.