Abstract: Kluyveromyces marxianus was used to ferment wheat bran as functional ingredient with natural enzymes, and celluase activity during fermentation was analyzed. The differences in dietary fiber composition and baking characteristics of wheat bran bread (B₁), fermented wheat bran bread (B₂), xylanase wheat bran bread (B₃), and composite wheat bran bread (B₄) were compared. The results indicated that K. marxianus exhibited abundant extra cellular β-glucosidase production ability with an enzyme activity of 6.98 U/g, exoglucanase and β-glucosidase activities increased to 6.06 and 21.70 U/g respectively, and insoluble dietary fiber (IDF) degraded gradually to 38.30 g/100 g during 48 h wheat bran fermentation. Reducing sugar content increased during dough mixing and fermentation, especially for fermented wheat bran enriched breads. Bread volumes, elasticity and water-holding ability of bread with fermented wheat bran were improved significantly (p<0.05), and its pores structures were more fine than unfermented wheat bran. No significant difference was showed in total dietary fiber (TDF) and araboxylan (AX) contents in four kinds of baked breads, and fermented wheat bran and xylanase could promote the dissolution of IDF and AX in bread.