The invention provides a suspended-type pipeline under-pressure sealing device used for binding a strapping tape on a leakage hole of a pipeline so as to seal the leakage hole. The suspended-type pipeline under-pressure sealing device is characterized by comprising a track mechanism and a tape coiling box; the track mechanism comprises two coaxially-arranged circular track units, and each circular track unit is composed of two semi-circular tracks; the tape coiling box is arranged between the two circular track units, wherein a sliding track extending in the circumferential direction is arranged on the side, far from the tape coiling box, of the external circumference of each semi-circular track; track wheels rolling along the sliding tracks are arranged on the two outer side faces of the tape coiling box correspondingly; a gear ring extending in the circumferential direction is arranged on the side, close to the tape coiling box, of the external circumference of each semi-circular track; gears engaged with the corresponding gear rings are installed on the track wheels; sliding grooves extending in the circumferential direction are formed on the inner sides of the gear rings, and rollers embedded in the sliding grooves are arranged on the outer side face of the tape coiling box; and a driving unit is arranged on the tape coiling box and used for driving the tape coiling box to move on the track mechanism.