An integrated structure of a preparation syringe includes a stretchable piston, a barrel, a needle, an exposed rubber plug, a sealing sheet, a built-in rubber plug, a sealing rubber plug and an engaging rubber plug. One end of the barrel is provided with the stretchable piston, and another end of the barrel is provided with a clamping column. The exposed rubber plug is provided on a side of the stretchable piston away from the barrel. The built-in rubber plug is provided within the barrel. A Scale mark is provided on a circumferential surface of the barrel. The sealing rubber plug is inlaid and sleeved on the clamping column. The sealing sheet is provided on a side of exposed tuber plug away from the barrel. A blunt end is provided at an end of the needle away form a needle tip. The engaging rubber plug is provided outside the blunt end.