Abstract: In order to isolate and screen out bacteria which could degrade straw cellulose efficiently,so as to promote the development and utilization of soil microbial resources and rice straw degradation in Ningxia.In this study,the soil under poplar forest in the Yellow River Diversion Irrigation Area of Yinchuan Plain at the eastern foot of Helan Mountain in Ningxia was used as test material.The culturable microorganisms were isolated and purified by using sodium carboxymethyl cellulose medium.The activity of methyl cellulase（CMCase）and the highest enzyme activity of filter paper were determined.The filter paper disintegration experiment,straw disintegration and degradation rate experiment were carried out.The results showed that 127 strains of bacteria were isolated and purified from the soil,and 13 strains had strong cellulose degradation ability among them;the D/d values of different strains,the highest enzyme activity of carboxymethyl cellulose,filter paper enzyme activity and filter paper degradation ability were different,and the maximum values were not the same strain.In conclusion,the strains number of 362,225 and 402 can be used for effecient degradation of rice straw.