An alignment exposure method and a method for fabricating a display substrate are disclosed. The alignment exposure method includes a first alignment exposure process and a second alignment exposure process. Multiple groups of alignment marks are provided at an edge of at least one side of the substrate in the first alignment exposure process. At least one group of mark structures are provided at an edge of at least one side of a mask employed in the second alignment exposure process. In multiple mask alignment processes in the second alignment exposure process, each group of the at least one group of the mark structures of the mask are aligned with groups of the alignment marks at a corresponding side of the substrate group by group. The alignment exposure method is employed to realize alignment exposure of a substrate with a size larger than a size of a mask.