Large-diameter steel pipe butt joint auxiliary connecting tool

The utility model provides an auxiliary connecting tool for butt joint of large-diameter steel pipes. The auxiliary connecting tool comprises a fixed locking piece, a movable locking piece and a locking device. A fixed chain of the fixed locking piece surrounds the end part of the fixed cylindrical steel pipe; the two ends of the fixed chain are locked through a locking device to form an annular fixed chain; the movable locking piece is annularly fixed in the middle of the circumferential surface of a cylindrical sliding sleeve in a sleeving manner; each movable connecting shaft plate is fixedly connected with a pair of corresponding chain shafts; a movable vertical plate is further perpendicularly fixed to the outer end of each movable connecting shaft plate, a through hole is formed in each movable vertical plate, the movable vertical plates and the bolts are sleeved together, and the fixed locking pieces and the movable locking pieces are made to be close to each other until the fixed locking pieces and th