Abstract: The influence of physical treatment on the yield of FOs from maize bran was investigated in this paper. In order to explore the function of physical treatment on FOs yield,the changes of composition and structure of maize bran cell wall was determined and the production of FOs was measured. Results indicated that FOs yield was improved 1.5 folds after high pressure steaming,the reason was that the composition of wheat bran cell wall was changed by high pressure steaming,and cellulose and pectin were released,the contact probability of cellulose and xylanase with wheat bran was increased. Cell wall of maize bran was decomposed by microwave treatment and extrusion process,and FOs yield was no obvious change.