Abstract: In order to investigate the influence of the factors such as the initial pH of fermentative medium, the kinds of carbon and nitrogen sources of fermentative medium and the types of inducers on CMC-Na (monosodium carboxymethylcellulose) cellulase activity of a new isolated producing cellulase strain from the rumen of sheep, the single factor and orthogonal test were respectively carried out. The CMC-Na cellulase activity was determined by DNS (3,5-dinitryl salicylate) method. The results displayed that the optimal initial pH value of fermentative medium was 5.0. The optimal carbon and nitrogen sources of fermentative medium were respectively starch and yeast extract and their optimal additive amount were respectively 1% and 0.4%. The optimal inducer was dry bran (1.5%). Under the optimal condition, the highest value of CMC-Na cellulase activity was 56.62U/mL. All these results indicated that this was a new founding for looking for strain producing cellulase and using Trametes trogii to produce cellulase by static fermentation showed some advantages such as short fermentation time, and lower energy cost as compared with the reported Aspergillus niger and Trichoderma. Therefore, this study will display some certain substantial economic significance.