The invention relates to a manufacturing method for a large-dimension diffraction grating and an exposure device thereof. The exposure device comprises two stages of micro modules and a zero-order suppression phase grating; the first-stage micro module is a 4F imaging system and the second-stage micro module is a double-telecentric micro projection interferometric imaging system; the second-stage micro module has a micro multiple larger than that of the first-stage micro module; and an imaging plane of the first-stage micro module forms an input plane of the second-stage micro module; and an output plane of the second-stage micro module forms a recording plane during exposure imaging. The first-stage micro module includes a first Fourier transform lens or lens set and a second Fourier transform lens or lens set. Besides, the zero-order suppression phase grating is arranged between the first Fourier transform lens or lens set and the second Fourier transform lens or lens set. When a stripe position in exposed spot needs to be adjusted, the zero-order suppression phase grating is translated along the direction perpendicular to the grid line, thereby realizing changing of the stripe position in the spot.