The invention provides an insulation step ladder and aims to solve the problem that it is difficult for workers to go in and out of equipotential when the distance between two strings of insulators exceeds 60 cm in the prior art. The insulation step ladder comprises two jumper wires and insulation cross-bars arranged between the two jumper wires. Two ends of each insulation cross-bar are both fixedly connected to a mounting base. Each mounting base comprises a base body, a first arc-shaped hoop plate, a second arc-shaped hoop plate and a detachable fastener, wherein the first arc-shaped hoop plate is arranged on the base body; the second arc-shaped hoop plate is rotatably connected on the base body; and the first arc-shaped hoop plate and the second arc-shaped hoop plate hold a jumper wire tightly through the detachable fastener. It is convenient to climb by the use of the insulation step ladder, and risk and labor intensity are reduced for workers. Workers don't need to accord with ''hand-and-foot synchronous and transverse movement'' required by the technology of ''striding over two insulators and short-connecting three insulators'' along two strings of insulators; and the problem that it is difficult for workers to go in and out of equipotential when the distance between two strings of insulators exceeds 60 cm in the prior art is solved.