The utility model discloses a mill flour technical field's a flour -milling machine is used in processing of polycrystalline silicon board, which comprises a frame, be provided with control switch, cylinder and silicon board fixed establishment in the frame, the sliding sleeve has been cup jointed on the cylinder, be provided with the fixed plate on the sliding sleeve, be provided with electric telescopic handle between fixed plate and the cylinder, it has the pivot to peg graft on the fixed plate, the bottom of pivot is provided with the mill flour wheel, the top of pivot is provided with little runner, be fixed with driving motor on the fixed plate, the utility model discloses being convenient for, it is fixed to clip the polycrystalline silicon board that needs carry out burnishing andpolishing, and it is tight to the clamp of polycrystalline silicon board to be convenient for to control splint through the hand wheel, through control electric telescopic handle, makes the upper andlower height of polishing of mill flour wheel can carry out comparatively convenient regulation.