The utility model discloses a circular power battery cover plate. The circular power battery cover plate comprises a circular base plate and a pole post, wherein the circular base plate is provided with a pole post hole through which the pole post penetrates; a sealing gasket is arranged between the pole post hole and the pole post; the upper surface of the circular base plate is provided with a circular die sunk step concentric with the pole post hole, and the lower surface of the circular base plate is provided with a square die sunk step concentric with the pole post hole; the root of the pole post is provided with an axially vertical square lug boss; the square lug boss is matched with the square die sunk step. The circular power battery cover plate disclosed by the utility model can bear greater riveting force, the riveting air impermeability between the cover plate and a battery is greatly improved, and the safety, convenience and practicability of the power battery are effectively improved.