The preparation of dietary fiber from wheat straw residual was studied by two extraction methods, NaOH and C2H5OH extraction. Single factor and orthogonal experiments were used to determine the best conditions. Results showed that, for the NaOH extraction of the dietary fiber, the optimum temperature, extraction time, concentration of the extracting reagent and amount of the liquid were room temperature, 60 min, 3% and 60 ml, respectively, while for the C2H5OH extraction, the best values of the above-mentioned factors were room temperature, 80 min, 100% and 70 ml, respectively. The extraction technologies were evaluated by analysis of the fiber contents in the extracts by neutral detergent and the determination of the properties of the extracted dietary fiber.