The utility model discloses a putty coating machine. The putty coating machine comprises a feeding mechanism, an air compressor (7) and a pressure spray gun. The feeding mechanism comprises a motor (2), a gear pump (1) and a feeding hopper (3). The motor (2) is connected with the gear pump (1), the feeding hopper (3) is vertically mounted on a feeding opening in the upper portion of the gear pump (1), a connecting pipe (4) is connected with the outlet end of the gear pump (1), and the connecting pipe (4) is connected with a feeding handle (9) of the pressure spray gun through a feeding hose (6). The air compressor (7) is connected with a feeding bin (11) of the pressure spray gun through an air inlet hose (8), and the air injection direction of the air compressor (7) is the same as the ejection direction of a nozzle. A feeding switch (10) is arranged between the feeding handle (9) and a channel of the feeding bin (11) of the pressure spray gun, so that an entire structure is formed. The putty coating machine has the advantages of being saving in manual work, simple to assemble and operate, even in coating, low in manufacturing cost, high in generalizability, capable of greatly improving working efficiency and the like.