Abstract:This paper used carboxyl methyl cellulose（CMC-Na）as the exclusive carbon source and preliminary screened cellulose-degrading strains from primeval forest soil under the rot wood in Luocheng Guangxi.From the study of their modality and physical-biochemical characteristic，combining Congo red dyeing，which could determine the diameter size of transparent circle for further judgment of cellulolytic ability.Finally obtained four strains and inoculated in liquid medium.From determination of endo-glucanase （CMCase）and filter paper enzyme activity，besides the Congo red staining method proved that the strain H-2 cultured on CMC screeningflat formed the largest transparent circle and colony diameter and had high CMCase producing ability.By liquit fermentation measuring enzyme activity found that CMCase activity reached 130 U/mL.H-2 was identified as Pythium acanthophoron by morphology and molecular identification.