In this paper, the transmitting characteristic of multimode fiber is improved by introducing the periodic scramble during the fiber′s drawing process. The scramble is some periodic and continuous left- or right-turning, so-called handness structure, by turning the fibers relative to the preform during the course of drawing process. The differential mode delay (DMD) test shows that this scrambling can reduce the split of optical pulse and improve the transmitting characteristic of multimode fiber.