The utility model discloses a convex welding base plate bended -arc mechanical equipment, including the frame bottom plate, frame bottom plate both sides are equipped with the frame curb plate, two blocks of frame curb plates correspond the setting, be equipped with two lower compression rollers between two blocks of frame curb plates, correspond on two blocks of frame curb plates and be provided with the spout, the cooperation the spout, be equipped with the support frame subassembly between two blocks of frame curb plates for the support frame subassembly can be followed the spout and reciprocated, install the compression roller on the support frame subassembly, it is equipped with the drive rocking handle to go up compression roller one end, install sliding lead screw on the support frame subassembly, the sliding lead screw upper end is equipped with the drive handle. The utility model discloses is it 500mm that diameter range just can be processed to convenient operation, security performance height 3000mm's arc band iron can be applicable to the various circular arc type welding base plate's of steel construction trade processing, especially the ring shape welding base plate of the interior stiffener of pipe class component.