The invention discloses a ventilation structure for a foaming mould. The structure comprises a first vent hole, a second vent hole, a piston groove, a dredging hole, a plug and a piston rod, wherein the first vent hole is communicated with the outside of the foaming mould; the second vent hole is arranged inside the foaming mould, and is communicated with the first vent hole; the top of the piston groove is communicated with the second vent hole; one end of the dredging hole is communicated with the bottom of the piston groove, while the other end is communicated with the outside of the foaming mould; the plug is arranged on the bottom of the piston groove; and the piston rod is arranged inside the piston groove; one end of the piston rod is adapted to the second vent hole, and can make piston motion relatively to the second vent hole; the outer surface in the middle of the piston rod is closely attached to the inner wall of the piston groove; and the outer diameter of the other end of the piston rod is less than the inner diameter of the piston groove, and corresponds to one end of the dredging hole. Therefore, the ventilation structure not only can reduce the production cost andimprove the working efficiency, but also can reduce the misoperation rate of operators.