The utility model belongs to the technical field of steel structure painting, and particularly relates to a steel structure painting device which comprises a foot stool, a base is installed on the foot stool, a first lead screw is rotatably installed on the inner wall of a sliding groove, two sets of sliding blocks are symmetrically assembled in the sliding groove, an installation frame is installed on the sliding blocks, a rotating plate is rotatably installed on the installation frame, and a first lead screw is installed on the first lead screw. A steel structure is clamped between the two sets of rotating plates, clamping blocks are installed on the rotating plates, a rotating rod is rotatably installed on one set of installing frames, the rotating rod is fixedly connected with the rotating plates, the rotating rod is fixedly sleeved with a worm wheel, two sets of fixing blocks are fixedly installed on the installing frames, worms are rotatably installed on the fixing blocks, and the worm wheels are fixedly connected with the worm wheels. The worm drives the worm gear on the worm to rotate, the worm gear drives the rotating rod to rotate, the rotating rod drives the rotating plate to rotate, the rotating plate drives the steel structure clamped on the rotating plate to rotate, direction adjustment of the steel structure is achieved, the steel structure is turned over, and turning convenience is improved.