Building decoration wall painting machine

The invention relates to a building decoration wall painting machine, and relates to the technical field of building machinery. The lifting guide rail mechanism comprises an upper guide rail, a lower guide rail and a lifting assembly, the upper guide rail and the lower guide rail are arranged in parallel up and down, the lifting assembly is used for adjusting the height of the upper guide rail and the lower guide rail and connected to the base, and the upper guide rail and the lower guide rail are connected to the lifting assembly; the paint supply mechanism is arranged between the two guide rails in a sliding mode and comprises a supply bin located on the upper portion and a receiving bin located under the supply bin, a supply port is formed in the side, close to the wall, of the bottom of the supply bin, and a receiving port is formed in the top of the receiving bin; and the painting mechanism is detachably connected to the paint supply mechanism and comprises a vertical scraping plate vertically connected