Aimed at the defects existed at the multi stage double acting cylinder sealing device,such as scratch failure,deformation and etc,the support rings was set up on both sides of the slip ring of the cylinder sealing device to avoid the slip ring lips to be squeezed into the oil hole and be scratched,double O-ring structure was used and the retaining ring was set up in the groove of O-ring to avoid the O ring to be bitten by the gap and the severe wear between the center piston rod and the adjacent cylinder.After improved,the reliable sealing of the multi stage double acting cylinder is ensured,the service life of the cylinder in the high-pressure is ptolonged.