The utility model provides a distribution automation overhauls cat ladder of usefulness, this cat ladder of includes first section cat ladder, second section cat ladder and supporting mechanism, and first inboard of section cat ladder is equipped with the slide, slides about second section cat ladder can be realized in the slide to through installing slide shutting realization second section cat ladder the fixing in the slide on first section cat ladder, the supporting mechanism includes the support arm of H type, and the one end of support arm is articulated mutually with the cat ladder crossbeam of the top of second section cat ladder, each articulated mount of the both sides of an upper end second cat ladder crossbeam of second section cat ladder, and spaced apart in the first half of mount have a plurality of recesses, and horizontal pole on the support arm is based on predetermines the angle in with its calorie of recess on the mount to through shutting screw fixed support arm's support angle, thereby form stable triangular structure. The utility model discloses can not only fully provided distribution automation overhaul uses of ascending a height, safe and reliable can receive and release foldingly moreover, and portable can improve maintenance operation work efficiency greatly.