The difference of cellulase achvity betWeen the alternate fermentahon of tWo fungi species and the fermentation of mono-fungus specie is studied, using, Pleurotus sajor-caju (Fr.) Sing. and Trichoderma linorum (Tode) Harz. The results show that cellulase activity by the alternate fermentahon of two fungi species is 15 times higher than the fermentahon of mono-fungus specie. ms provides a new emyme fermentahon technology for increasing output and achvity of cellulase.