Abstract: Improper disposal of crop straw might have negative effects on rural ecological environment. At present, the main way of straw disposal in Northeast China is to smash and return the straw to the field directly. However, the straw is not easily decomposed in natural environment, which affects the spring ploughing. Therefore, it is important to find new types of culturable strawdegradation bacteria from the perspective of adding exogenous microorganisms to promote straw insitu decay. In this study, the potential highefficiency cellulose degrading bacteria were isolated and screened from the rotten straw and cattle intestines by enrichment culture, primary screening of Congo red culture medium, and disintegration test of filter paper. The optimum growth temperature and pH were assessed. The actual degradation ability of the strains was investigated in liquid fermentation culture. Five strains with high degradation ability of corn straw were obtained. The growth peaks of the five strains occurred in the range of temperature 20-30 ℃, pH 7.5-8.5. After 15 days of liquid fermentation, the weight loss rate of straw by the five strains was in the order of NX9 (53.88%) > NF6 (51.36%) > JF3 (46.97%) > JZ8 (45.2%) > JX4(35.79%)> CK (23.88%). Among them, strain NX9 (temperature 30 ℃, pH 7.5) had the strongest degradation ability to straw hemicellulose and lignin, with the degradation rate of 48% and 37.7% in 15 days, respectively. Strain NF6 and JF3 belong to cold resistant bacteria. Especially, strain NF6 can grow and propagate at 4 ℃. Our results provide a basis for developing the technology of “exogenous microorganism promoting straw in situ decay” in northern China.