The invention provides a building construction wall cleaning device which effectively solves the problems that in an existing wall cleaning technology, especially as for cleaning of walls at corners,the efficiency is low, manual labor is large, the cleaning force is large, and cleaning quality is poor. According to the technical scheme, the building construction wall cleaning device includes a rectangular box, a central shaft is arranged in the rectangular box, rotating shafts are arranged on the left side and the lower side of the central shaft, incomplete gears are arranged on the rotatingshafts, a plurality of racks are arranged between the rotating shafts and the side wall of the rectangular box, tension springs are arranged at the ends, far away from the central shaft, of the racks,a relieving tool is arranged on the outer side of the rectangular box, a telescopic rod is arranged on the end surface of the relieving tool, a sliding slot is formed in the side wall of the rectangular box, and the lower end of the telescopic rod and the racks are fixed; and a cylindrical block is arranged on the central shaft, L-shaped steel is arranged on the upper right side of the rectangular box, a plurality of L-shaped scrapers are arranged on the outer side of the L-shaped steel, a through groove is formed in the upper right corner of the rectangular box in the front-rear direction, aplurality of ejection rods are arranged in the through groove, the right ends of the ejection rods slantly and upwards protrude out of the rectangular box to be fixed to the L-shaped steel, and the outer circular surface of the cylindrical block is provided with a cam groove.