The invention discloses an application method of a tool for repair plate fastening in pipe repair. The used tool comprises a T-shaped rod, a thread disc, a connecting nut, a rotating piece and base arranged in sequence from top to bottom. As all the parts are reasonably designed, the tool can realize the dismounting and mounting process without needing special operation spanner, and the pipe repair plate fastening is quickly realized. In addition, the connecting structures of the T-shaped rod, the connecting nut and the rotating piece are reasonably designed, the several parts are more convenient and labor-saved in disassembly. The tool can fasten pipes with different shapes and different sizes. The tool can greatly improve the repair plate fastening efficiency in pipe repair; and in addition, as enough operation space is reserved around a repair plate when the tool fastens the repair plate, the continuous welding process of the repair plate can be realized, and the welding effect is good. The method can effectively improve the pipe repair efficiency.