Abstract: Since the ring fiber bundle has the advantages of coaxial illumination, uniformly emitted light and shadowlessness, it has been widely used in machine vision, optical instruments, image processing and so on. Proceeding from the illumination mode of ring fiber bundles, the fiber bundles of single ring, double rings, multi rings, small obliquity (0°～30°), large obliquity（30°～60°）and axial direction in direct illumination mode, and the fiber bundles of dome-lick structure, diffused structure and leaky structure in indirect illumination mode are elaborated. The characteristic of the structures and applications of the ring fiber bundles are summarized and the notes in manufacturing the ring fiber bundles are presented.