The utility model discloses a scalable insulating ladder, include a plurality of grades of terraced bodies that cup joint each other and set up in the positioning mechanism who controls reciprocal anchorage between flexible pulley mechanism of terraced body and the control terraced bodies at different levels on it, the ladder body be the integral box body of top end opening, and the top of inboard terraced body is connected with work platform, and a plurality of grades of ladders have been seted up to the edge direction of height on the lateral wall of terraced body, the inboard terraced body of pulley mechanism controls upwards slides and is fixed a position by the positioning mechanism completion after length satisfies the operation requirement, and the staff carries out the operation in the operation post is entered to the ladder. It is thus clear that the utility model discloses a with terraced body design for the integral box body of top end opening, guaranteed the wholeness and the stability of terraced body, avoid the operation personnel to climb that becoming flexible appears in terraced in -process or even the unexpected condition such as scatter.