The embodiment of the invention discloses a loudspeaker voice diaphragm forming die, and the die comprises a die body. The bottom surface of the die body is provided with a ventilation groove. The die body is also provided with a gap passing through the die body, and the ventilation groove is communicated with the gap. Moreover, the section area of the ventilation groove is greater than the section area of the gap, so as to enable the ventilation groove and the gap to form an air exhaust channel. According to the above mode, the bottom surface of the die body is provided with the ventilation groove. Because the die body has the through gap, air will pass through the gap to reach the ventilation groove, and the ventilation groove and the gap form the air exhaust channel, thereby shortening the air exhaust path during the forming of a voice diaphragm, and improving the ventilation performance of the die during forming. Moreover, there is no need to change the thickness of a die material, and the rigidness is improved. The ventilation groove is convenient to manufacture, thereby improving the production efficiency and reducing the production cost.