Wall painting device with liquid self-supply function

The invention discloses a wall painting device with a liquid self-supply function. The wall painting device comprises a base plate, a stirring barrel, a pumping mechanism, a lifting cavity, polishingmechanisms, a smearing roller and a forward and reverse rotation motor; the stirring barrel is arranged at the upper end of the base plate; the pumping mechanism is arranged on the left side of the stirring barrel and comprises driven gears, a driving gear, a threaded sleeve, a second threaded rod, a piston, a cylinder, a rotating rod, a first liquid guide tube and a second liquid guide tube; thelifting cavity is formed in the left side of the pumping mechanism; rectangular grooves are formed in the left and right ends of the lifting cavity; a supporting plate is fixedly installed at the leftend of a moving block and connected with a protecting cover through a supporting rod, and the smearing roller is rotationally connected in the protecting cover; the polishing mechanisms are symmetrically arranged at the upper