Embodiments of the invention provide a mask plate, a method for fabricating an array substrate using the mask plate, and an array substrate. The mask plate is used for fabricating the array substrate by a stitching exposure. The mask plate comprises 2n+1 mask patterns successively arranged and parallel to each other, where n is any natural number, each mask pattern includes a light-shielding pattern corresponding to a portion of a data signal line on the array substrate. The light-shielding patterns of two adjacent mask patterns are discontinuous, and the portions on both sides of the light-shielding pattern of the mask pattern located in the middle of the mask plate are asymmetric.