We present a grating imaging scanning lithography system for the fabrication of large-sized gratings. In this technology, +(-)1-order diffractive beams are generated by a phase grating and selected by a spatial filter. Meanwhile, a 4f system enables the +(-)1-order diffractive beams to form a grating image with a clear jagged-edge boundary on the substrate. A high-precision two-dimensional (2D) mobile stage is used for complementary cyclical scanning, thereby effectively eliminating image stitching errors. The absence of such errors results in a seamless and uniform large-sized grating. Characterized by a simple structure, high energy use, and good stability, this lithography system is highly relevant to the high-speed and cost-effective production of large-sized gratings.