Folding ladder for maintenance of transformer

The utility model provides a folding ladder for transformer maintenance, which comprises symmetrically arranged side plates and U-shaped frames symmetrically hinged between the side plates, extension frames are respectively hinged in the U-shaped frames, clamping plates are movably arranged on the outer walls of two opposite sides of one of the U-shaped frames, and the clamping plates are movably arranged on the outer walls of two opposite sides of the other U-shaped frame. When in use, the two U-shaped frames are turned over and positioned on the same horizontal plane, the clamping plates are respectively clamped on the two U-shaped frames so as to enable the horizontal plane of the U-shaped frames to be fixed, and then the extension frames are turned over and clamped on the U-shaped frames and positioned on the same horizontal plane with the U-shaped frames, so that the length of the U-shaped frames is increased by the extension frames; during storage, the extension frames are separated from the U-shaped fr