The invention disclose a paper tube coating machine, wherein a driving feeding roller, and a driven feeding roller capable of moving along a horizontal direction are arranged to form rolling support to a paper tube; and an extrusion roller capable of lifting along a vertical direction is arranged to form extrusion to the outer circumferential surface of the paper tube so as to tightly fit the paper pasted on the outer circumferential surface of the paper tube with the outer circumferential surface of the paper tube; the adjustment of the driven feeding roller along the horizontal direction and the adjustment of the extrusion roller along the vertical direction ensure the paper tube coating machine to be suitable for coating different paper diameters of paper tubes so as to have good practical performance. The paper tube coating machine is simple in structure, convenient to operate in the coating process; the outer circumferential surface of the paper tube after coating is smooth and flat; and the paper tube coating machine is used to coat the paper tubes to effectively improve the coating work efficiency of the coating machine.