Using rye bran as raw material， dietary fiber was prepared by enzymatic method， and the structure， monosaccharide and phenolic composition and functional properties of the two dietary fibers were determined respectively. The results showed that the surface of soluble dietary fiber (SDF) was loose， which was mainly composed of arabinose (68%)， galactose (13.1%) and xylose (12.2%). The surface of insoluble dietary fiber (IDF) was porous and irregular， which was mainly composed of xylose (54%) and arabinose (38.3%). Both dietary fibers had infrared characteristic absorption peaks of sugars. The crystallinity of IDF was higher than that of SDF， and the structure was more regular. SDF showed better water absorption (2.19 g/g)， cholesterol adsorption capacity (2.09 mg/g，pH=7) and nitrite adsorption capacity (327 μg/g，pH=2). The composition and content of phenolic substances in IDF were significantly higher than that in SDF (P < 0.05). The phenolic substances of IDF and SDF were mainly bound ferulic acid.