Abstract: To study the enzymatic extraction technique and the physicochemical properties of pentosans from black-grained wheat bran. The effect of xylanase quantity, extraction temperature, p H, time duration, ratio of material to liquid on the yield of pentosan were studied by single-factor experiments and the technology parameters were optimized by orthogonal experiment. The optimized parameters were:extracting for 90 min at60℃, p H6, with pentosanase quantity of 12mg/10 g substrates and 1 ∶10 ratio of material to liquid. Under the optimum conditions, the yield of EEP was 4.17%. Physicochemical properties of EEP were analyzed using GC, and HPLC instruments. The results showed that EEP was composed mainly of arabinose, xylose, glucose, and trace amount of galactose, mole ratio of Ara∶Xyl∶Glc=1.0∶1.55∶3.19. The Ara/Xyl value was 0.64. It had a relative low Mw of 2.16×104.