The light guide plate (LGP) as the backlight of the liquid crystal display (LCD), has been applied widely. The manufacturing principle arranging the reflection point on the surface of the the LGP material. Currently LGP for lighting is manufactured by screen printing and laser engraving. Laser engraving is more personalized, flexible and green, but the traditional laser engraving way, whose efficiency is too low, is lack of processing optimization. A methodology of laser dots marking that based on dynamic focus galvanometer system is proposed.The corresponding process optimization method is developed. It improves the effectiveness and efficiency of processing significantly.