The invention provides an energy accumulator tank extrusion die. The die comprises a male die seat, a punch and a female die; the punch comprises an annular punch body and a punch core capable of being arranged in an inner cavity of the annular punch body in a penetrating manner, the upper end of the annular punch body is fixedly connected to the lower end face of the male die seat, and when the punch core is pressed in the vertical direction, the punch core can vertically slide relative to the annular punch body; the female die is an annular columnar body and is located below the punch; an upper die cavity and a lower die cavity capable of facing the punch are formed by the female die, and the inner diameter of the lower die cavity is smaller than that of the upper die cavity; a gap exists between the upper die cavity and the punch, and a gap exists between the lower die cavity and the punch; and the outer diameter of the annular punch body is matched with the inner diameter of the upper die cavity, and the outer diameter of the punch core is smaller than the inner diameter of the lower die cavity. The energy accumulator tank extrusion die can effectively prevent the phenomenon that in the extrusion process of the bottom of a cup-shaped blank, bending deformation happens, the upper hole diameter and the lower hole diameter of a hole cavity of the cup-shaped blank are completely consistent, and the coaxiality of a finished product is ensured.