Abstract: It is a development direction of present feed industry to produce fermented feed with cellulose-decomposing microorganisms ,which can hydrolyze cellulose into monosaccharides In this trial,12 strains of fungi for decomposing cellulose were chosen from soil and feed. On the basis of these strains, 6 suitable strains were obtained through the experiments of decomposition of filter paper, determinations of CMC enzyme activity, FPA enzyme activity and natural cellulase activity. The experimental results showed that the enzyme activity varied with the content of natural cellulose in the culture medium.