Abstract: In order to develop a natural, safe improver of steamed bread and nutrition fortifier, as well as increase the added value of wheat bran, phenolic xylans from wheat bran with different addition level (0.25%, 0.5%, 1.0%, 2.0%) and molecular weight (82°, 581kD) were chosen and their effects on fermented dough properties and qualities of steamed bread were investigated. Low molecular weight phenolic xylans were obtained by ultrasonic degradation of phenolic xylans. The rheometer and low-field nuclear resonance (NMR) were used to observe the changes of fermented dough properties with phenolic xylans. The texture profile analyzer was used to observe the changes of qualities of steamed bread with phenolic xylans. The viscoelasticity, water distribution and mobility of fermented dough, color, texture, sensory evaluation score of steamed bread were evaluated in the experiment. The results showed that along with the increase of phenolic xylans from wheat bran, the elastic modulus and proton density A22 increased then decreased, viscous modulus and proton density A23 increased, relaxation time T22 of fermented dough decreased. The lightness and adhesiveness decreased, redness and yellowness increased, specific volume, cohesiveness, resilience and sensory score of steamed bread increased and then decreased, hardness and chewiness of steamed bread decreased and then increased with increasing addition level of phenolic xylans from wheat bran. The higher molecular weight of wheat bran phenolic xylans was, the larger quantitative change of the elastic modulus and viscous modulus would be. The high molecular weight wheat bran phenolic xylans had long relaxation time T22 and small proton density A21 of fermented dough. When the molecular weight of wheat bran phenolic xylans was low, the specific volume and springiness of steamed bread were large, but the hardness and chewiness of steamed bread were relatively large. Compared with the control group, the addition of phenolic xylans from wheat bran could improve the rheological properties and water properties of fermented dough and quality of steamed bread. When the content of wheat bran phenolic xylans was 0.5%, the improvement effect of fermented dough and steamed bread qualities was best. When the addition level of wheat bran phenolic xylans was lower than 1.0%, the properties of fermented dough and qualities of steamed bread were improved. However, the properties of fermented dough and qualities of steamed bread deteriorated when phenolic xylans content was 2.0%. The improvement effect of properties of fermented dough and qualities of steamed bread with high molecular weight wheat bran phenolic xylans was better than low molecular weight wheat bran phenolic xylans. The method and data stated in this study were useful and valuable to the industry and can provide the theoretical basis for phenolic xylans widely application to the flour products.