The utility model belongs to the technical field of marine work equipment, and relates to a rack butt joint jig frame of a marine work platform. The rack joint jig frame comprises a brace, a strengthening rib, a flat plate, rotators, a baffle, racks, screw rods and a support plate. The flat plate is arranged at the upper portion of the brace, the strengthening rib is welded between the flat plate and the brace, the baffle is welded to the back portion of the flat plate, the support plate is welded to the front portion of the flat plate, the racks are placed between the support plate and the baffle, two screw holes are formed in the support plate, the screw rods are installed in the screw holes, and one rotator is installed at one end of each screw rod. One rotator is installed at one end of each screw rod, and the other end of each screw rod abuts against the racks. The rotators are rotating gears, and the two rotating gears are meshed with each other. When butt joint is carried out on the racks, a welding gap between the front rack and the back rack placed on the jig frame can be adjusted, positioning is convenient and accurate, components needed in the rack butt joint jig frame can be obtained for a shipyard, the manufacturing cost is low, and the effect is large.