The invention discloses a revolving-extrusion sealing device for pipe sealing machines. The device is characterized by comprising a main shaft, a cutter head, a sealing cutter, a sealing cutter guide mechanism and a cutter moving mechanism, wherein the cutter head is arranged at the front end of the main shaft, and the sealing cutter is arranged on the cutter head; the main shaft is driven to rotate by a main shaft driving mechanism; under the guidance of the sealing cutter guide mechanism, the sealing cutter slides along the direction perpendicular to the axis of the main shaft so as to moveclose to or far away from the axis of the main shaft; and the cutter moving mechanism drives the sealing cutter to slide along the sealing cutter guide mechanism. The revolving-extrusion sealing device disclosed by the invention has the advantages that 1, the main shaft driving mechanism drives the main shaft to drive the cutter head to rotate, so that the sealing cutter rotates circumferentiallyalong the main shaft; meanwhile, the cutter moving mechanism drives the sealing cutter to slide along the sealing cutter guide mechanism, so that the sealing cutter slides along the direction perpendicular to the axis of the main shaft so as to move close to or far away from the axis of the main shaft, therefore, the revolving-extrusion sealing processing on an open end of a pipe to be processed can be realized, and finally, a sealing wall perpendicular to the side wall of the pipe to be processed is formed, the thickness of the sealing wall is consistent, and the end sealing effect is good; and 2, the whole revolving-extrusion sealing device is simple and compact in structure, and convenient to control.