The invention discloses a pressure cylinder device of a double-bang firework automatic moulding machine. The pressure cylinder device of the double-bang firework automatic moulding machine is characterized by comprising a pressure cylinder driving mechanism, a guide rod, a pressure cylinder push plate and fixing cylinder rods; one end of the pressure cylinder driving mechanism and one end of the guide rod are correspondingly connected with one end surface of the pressure cylinder push plate; the multiple fixing cylinder rods are arranged and connected to the other end surface of the pressure cylinder push plate in parallel; and the pressure cylinder driving mechanism and the guide rod are correspondingly connected to a frame above a cylinder column in a punching, inserting and lead leveling station of the double-bang firework automatic moulding machine in a through manner; and therefore, the pressure cylinder driving mechanism drives the pressure cylinder push plate to drive the fixingcylinder rods to press down and fix a double-bang firework cylinder body by corresponding to the position of one port of the double-bang firework cylinder body on the cylinder column. The pressure cylinder device of the double-bang firework automatic moulding machine has the advantages that the operation in a follow-up procedure of a product and the quality of a finished product are guaranteed, the pressure cylinder device of the double-bang firework automatic moulding machine is suitable for assembling the double-bang firework automatic moulding machine which needs to seal an opening of a packaging paper outside the cylinder body and so on.