The utility model provides a pressing device for joint is withheld to pipeline, the device's front end backup pad with the tail end backup pad links together through four horizontal guide pillars, andboth ends are fixed through the round nut, and middle movable plate passes through the sliding sleeve and also installs on the horizontal guide pillar to but horizontal guiding post horizontal slip,two hydraulic jack afterbodys are fixed in the front end backup pad, the front end is equipped with the connecting seat, the connecting seat passes through the bolt fastening and arrives on the middlemovable plate, the outer support cover interference fit that detains inlays in the front end backup pad, outer buckling die piece or interior bloated support cover are inlayed middle movable plate isfixed through mounting flange, and the mould seat is connected to through the shaft hole cooperation in the tail end backup pad.