This application provides a top cover of a power battery and a power battery, the top cover includes a top cover sheet, a first electrode unit and a second electrode unit, the first electrode unit includes a turning sheet, an insulating piece and a current cutting-off structure, the current cutting-off structure is fixed in radial projection range of an assembling hole and is electrically connected with the top cover sheet, the turning sheet is fixed at an underneath of the top cover sheet through the insulating piece, the turning sheet is electrically connected with the top cover sheet merely through the current cutting-off structure, and the turning sheet is capable of turning and breaking the current cutting-off structure when an internal pressure of the power battery exceeds a reference pressure, so as to cut off an electrical connection of the current cutting-off structure with the top cover sheet.