In order to obtain cellulose-degrading bacteria, humus soil isused as the strain source to screen and isolate cellulose-degrading bacteria. A cellulose degrading bacterium numbered YBX-52 is obtained from culturing CMC-Na as the sole carbon sourceon a plate coated with soil sample diluted in a certain proportion and screening the strain with transparent circle by Congo red staining. The filter paper enzyme activity (FPA) measured by DNS method is 221.75 mol/min and the carboxymethylcellulose enzyme activity (CMC) is 274.56 mol/min when cultured at 30 ℃ for 48 h in enzyme-producing medium. The YBX-52 phylogenetic tree is constructed by sequence comparison with 16SrDNA, and identified as Bacillus thuringiensis according to its physiological and biochemical characteristics.