Abstract: Microbial component diversity of a composite bacterial system, being capable to degrading lignocellulose efficiently, was analyzed using denaturing gradient gel electrophoresis(DGGE) on the basis of 16SrDNA and plating. Nine aerobic bacterial isolates, isolate-1 to isolate-9, were isolated from peptone cellulose solution medium using plate cultivation, and the similarities of sequences of 16SrDNA between nine pure isolates with Pseudoxanthomonas taiwanensis, Tepidiphilus margaritifer, Bacillus sp. E53-10, Proteobacterium S072, Beta proteobacterium HMD444, Rhizobiaceae str. M100, Petrobacter succinimandens BON4, Bacillus thermoamylovorans, Paenibacillus sp. SAFN-016 were 97.5%, 99.0%, 98.4%, 100%, 98.9%, 99.3%, 98.1%, 99.5%, 99.8%, respectively. In addition, five bands of band A, band B, band C, band D and band E were detected using DGGE besides nine bands of pure isolates, and similarities of 16SrDNA V3 region betwen five bands with Ureibacillus thermosphaericu, Clostridium thermosuccinogenes, Clostridium thermopalmarium, Uncultured Clostridium sp. clone A1-3 and Uncultured bacterium tbr4-24 were 100%, 95.3%, 96.3%, 97.0% and 95.7%, respectively. After inoculating, 81.3% of rice straw weight was degraded under static condition within the first three days at 50℃. Aerobic bacteria and facultative bacteria were coexisted in one composite bacterial system, resulting in high bacterial component diversity and high capacity of lignocellulose degradation.