The utility model provides a two -way sealing packing ring, including the mounting hole, the erection column, the extension spring, the phase change material ring, the refrigeration piece, the rubber pad, the gasbag, the locating hole, ring lamella main part, reference column and collude the board, the refrigeration piece is installed in phase change material ring outer end, the assembly of phase change material ring is in the extension spring outer end, the mounting hole has been seted up in the extension spring, the erection column is installed to the extension spring upper end, the erection column assembly is inside the mounting hole, this design can reduce the temperature of piston rod, ring lamella main part upper end is provided with colludes the board, the reference column is installed to ring lamella main part upper end, the board left side is being colluded in the reference column setting, install the gasbag on the ring lamella main part inner wall, the last rubber pad of installing of the inner wall of the air bag, the locating hole has been seted up to ring lamella main part lower extreme, the reference column is installed inside the locating hole, this design has improved the job stabilization nature of piston pneumatic valve, the utility model discloses convenient to use, the operation of being convenient for, stability is good, and the reliability is high, has prolonged the live time.