The invention relates to an automatic zipper sewing device, a sewing machine and a sewing method, and belongs to the field of industrial sewing automation. A piece of upper cloth, a piece of lower cloth and a zipper to be sewed are placed on a sewing substrate, a sliding rack is raised away from the sewing substrate through a tilting cylinder, a large moveable plate is moved to a position for sewing the zipper through a push component, and then the purpose of feeding materials is achieved; fixation of the zipper and edge folding of the upper cloth and the lower cloth are completed by using an air sucking component, a zipper fixing groove, a zipper fixing component and an air blowing component, and thus the problems that the production efficiency is low and the quality is not stable as multiple sewing procedures cannot be completed at one time can be solved.