Feruloyl oligosaccharides(FOS) were prepared from maize bran using xylanase and cellulase. The effect of temperature, pH, enzyme dosage, substrate concentration, and reaction time on the production of FOs was studied. The optimum reaction conditions were obtained by orthogonal test as follows: temperature 60℃, pH5.0, reaction time 36h, xylanase concentration 6g/L, cellulase concentration 8g/L, substrate concentration 167g/L. Under the optimal conditions, the concentration of FOs reached 2.127mmol/L.