An alignment film printing device, configured to improve coating quality of an alignment film, includes at least one printing unit, and the printing unit each includes: a cylinder body with an opening at a bottom and an extract opening on a top; a vacuum extractor connected with the extract opening; a plunger provided inside the cylinder body, and configured to draw the alignment fluid from the opening to the cylinder body; a vacuum tester provided at the extract opening and configured to monitor a vacuum degree inside the cylinder body and above the plunger; a range finder provided inside the cylinder body and configured to monitor a distance from the plunger to a top of the cylinder body; and a control device in signal communication with the vacuum extractor, the vacuum tester and the range finder respectively and configured to control a volume of the alignment fluid drawn into the cylinder body according to test values of the vacuum tester and the range finder.