Scanning Dammann lithography(SDL)is proposed and implemented,which uses a Dammann grating to generate multiple beams with sharp step boundary for writing large-sized gratings efficiently.One of the most attractive advantages is that this technique can accelerate the writing speed,e.g.1×32 Dammann grating can be 32 times faster than the single laser scanning system.More importantly,the uniformity of the multi-beams-written lines is much better than the single laser beam scanning system in consideration of the environmental effects such as air turbulence,thermal instability,etc.Using the SDL system,a three-port high-efficiency beam splitter at visible wavelengths is fabricated quickly,and the theoretical and experimental diffraction efficiencies are both higher than 90%.Therefore,SDL should be a useful tool for fabrication of large-sized gratings. Scanning Dammann lithography (SDL) is proposed and implemented, which uses a Dammann grating to generate multiple beams with sharp step boundary for writing large-sized gratings. One of the most attractive advantages is that that technique can accelerate the writing speed, eg1 × 32 Dammann grating can be 32 times faster than the single laser scanning system. More importantly, the uniformity of the multi-beams-written lines is much better than the single laser beam scanning system in consideration of the environmental impact such as air turbulence, thermal instability, etc. Using the SDL system, a three-port high-efficiency beam splitter at visible wavelengths is fabricated quickly, and the theoretical and experimental diffraction efficiencies are both higher than 90%. Therefore, SDL should be a useful tool for fabrication of large-sized gratings.