The invention relates to a floating sterile drinking water storage device and belongs to the technical field of water quality deep treatment of domestic drinking water.The drinking water storage device comprises at least a pair of negative electrode and positive electrode, an electrolysis power supply providing power to the negative electrode and the positive electrode, and a water container.A water-permeable partition membrane is arranged between the negative electrode and the positive electrode in the pair.A window is formed in the top of the water container.The negative electrode is arranged at the bottom in the water container.The positive electrode is arranged outside the window in the top of the water container, the window is provided with a guide rail extending to the inner bottom of the water container, and the positive electrode and the water-permeable partition film are encapsulated into an integrated unit by an insulating frame.When water is contained in the water container and used, the integrated unit slides up and down along the guide rail under the action of buoyancy of water, the negative electrode makes contact with water in the water container, and the positive electrode makes contact with the water container through seepage water seeping from the water-permeable partition membrane.The drinking water storage device has the advantage that effective degradation of organic matter in water is conducted continuously on drinking water of a family terminal.