A manufacturing method for a light splitting grating based on precision ruling and thin film deposition technologies was presented.The black-white grating with a duty cycle of 0.5 was ruled by a ruling machine on the metal film,then,it was fabricated into a mask for the light splitting grating.After exposuring and developing photoresist on the K9 glass behind the mask,the rectangle relief grating consisting of photoresists was formed.In the range of theory design error,a SiO2 rectangle grating master could be obtained a after SiO2 film was deposited on the relief grating and the rest photoresists were removed.Finally,an epoxide resin light splitting grating was duplicated successfully.The experimental results show that the error of the intensity ratio of secondary light beam to read-write main light beam can be controlled in ±0.03 by using the complementarity of the mismatching tolerance between lengthwise direction and cross direction of the light splitting grating.