Abstract: Wheat bran is an excellent source of dietary fiber from a wide range of sources. Insoluble dietary fiber (IDF) is the main component of IDF, and the study on the influence mechanism of IDF on products can provide a theoretical basis for the preparation of high dietary fiber flour products. Adding dietary fiber into flour products can effectively improve the problem of inadequate intake of dietary fiber and improve its application value. In this study, IDF with a high purity was extracted and added to flour to prepare mixed flour with IDF content of 0%, 3%, 6%, 9%, 12%, and 15%. The effect of IDF content on dough rheological properties and noodle quality was studied. The results showed that the water absorption, formation time and weakening degree of the dough were positively correlated with IDF content, and the stability time was negatively correlated. The results of low field NMR showed that IDF could affect the distribution of water molecules in dough, and the addition of IDF could promote the conversion of deep bound water and free water to weak bound water. Viscosity tests showed that IDF improved the thermal stability of the system, reduced the gelatinization viscosity and recovery value, and inhibited the aging of starch. In addition, IDF increased the cooking loss rate of noodles, reduced the water absorption rate of noodles, and shortened the optimal cooking time. In the test of texture and tensile characteristic, the hardness, elasticity, chewiness, tensile force and tensile distance of noodles were significantly increased when the IDF supplemental level was less than 6% (P<0.05), while the quality above mentioned were significantly decreased when the IDF supplemental level was more than 6% (P<0.05). A small amount of IDF can strengthen the gluten network structure, while too much IDF will destroy the gluten structure and adversely affect the quality of noodles. Moreover, the color of noodles was negatively correlated with the amount of IDF, and significantly decreased (P<0.05) along with the IDF decreasing. The results showed that proper extension was conducive to the formation of the dough network structure, while the excessive addition of IDF would destroy the stability of the dough, reduce the ductility of the dough, and deteriorate the operability. Six percent of IDF was the optimal amount for making noodles. The results showed that IDF could inhibit the aging of starch, improve the thermal stability of the system, and significantly affect the quality of noodles (P<0.05). The texture quality of noodles prepared with 6% additive content was the best. This study is of great significance for expanding the application of wheat bran dietary fiber in flour products.