The present application provides a top cover of power battery, including top cover plate, first electrode unit and second electrode unit, the first electrode unit includes insulation piece, conductive plate, deformable plate and sealing piece, the top cover plate is provided with deformable plate connecting hole and fixing hole, the deformable plate seals the deformable plate connecting hole, the insulation piece is provided with top cover plate connecting portion and conductive plate connecting portion, the insulation piece is fixed underneath the top cover plate through cooperation of top cover plate connecting portion and fixing hole, the conductive plate is insulated from and fixed with the top cover plate through the conductive plate connecting portion, the conductive plate is electrically connected with the deformable plate, the sealing piece seals path from the fixing hole to interior of the power battery passing through gap between insulation piece and top cover plate.