The invention relates to a cover plate for an electric double-layer capacitor and an electric double-layer capacitor. The cover plate is provided with a terminal and a liquid injection hole, wherein the liquid injection hole is positioned on the terminal and is vertically formed downwards along the axial direction of the terminal. The electric double-layer capacitor is provided with the cover plate, wherein the liquid injection hole of the cover plate is vertically formed downwards along the axial direction of the terminal. The cover plate for the electric double-layer capacitor is not required to be thickened for strength improvement, and has explosion protection and pressure relief functions; and since a cover plate structure is adopted by the electric double-layer capacitor, the internal effective volume is expanded, the capacity of the entire electric double-layer capacitor is increased, phenomena such as shell bulging, valve explosion and the like of the electric double-layer capacitor are avoided, and the service life is prolonged.