The invention discloses an automatic cleaning platform for an insulating layer of an external wall of building construction. The automatic cleaning platform comprises a first installation box, a second installation box is fixed on the first installation box, a storage battery is fixed in the second installation box, the storage battery is electrically connected with an electric push rod, the electric push rod is fixed on the first installation box, a piston rod of the electric push rod is in threaded connection with a pushing block, a scraping knife is fixedly connected on the pushing block, the scraping knife is positioned on the outer portion of the front side of the first installation box, the front end of the scraping knife is in close contact with a wall, supporting mechanisms are arranged on two sides of the upper portion of the scraping knife, the supporting mechanisms are installed at the front end of the second installation box, connecting seats are welded on two sides of thetop end of the second installation box, lifting steel wire ropes are fixed on the connecting seats, a lifting mechanism is arranged at one end, far away from the corresponding connecting seat, of eachlifting steel wire rope, and platform limiting mechanisms are symmetrically arranged at the ends of the left end and the right end of the first installation box and the second installation box. The insulating layer on the wall can be automatically removed without labor, the safety is good, and the working efficiency is high.