The utility model discloses a collapsible second order hydraulic pressure ladder of ascending a height belongs to the device field of ascending a height. Its technical scheme's main points are: including first ladder, second ladder, the second ladder is connected and can be taken in in the inside of first ladder through slide rail and first ladder, first ladder side is fixed with four hydraulic cylinder, fixedly connected with lifter plate on the hydraulic cylinder lifter. The utility model discloses in the work of the operation and maintenance management of mainly used transformer substation, its have save space, convenient to use's advantage.