Abstract: In order to enlarge the application of the cellulose in food field and improve its taste and grade of quality, the authors design the experimental process of preparing water-soluble food cellulose with bran of grain corn as the raw material and cellulose as the enzyme preparation, and analyze such important evaluation indexes as enzymolysis rate, mass concentration and polymeric degree of reducing sugar as well as their testing methods. The experimental results show that the prepared product has water-solubility; the enzymolysis rate of the final product produced by three-step hydrolysis of enzymolysis method can reach as high as 86%; the polymeric degree is about 4. Otherwise, the authors also give a brief analysis on the characteristics of enzymolysis method, inexpensive raw materials and the market prospects of the products.