【Objective】No-tillage and straw mulching are two important techniques in soil building. It is, therefore, of great significance to understand effects of the two on diversity of the cellulose-decomposing bacteria (CDB) community in the soil. To this end, analyses were done of effects of long-term no-tillage and straw mulching on diversity of CDB, microbial community structure, and richness and dominance of CDB, so as to provide a theoretical basis for the study and demo-extrapolation of the technique of conservation tillage. 【Method】A long-term experiment, designed to have four tillage treatments, i.e. tillage with mulching (W_tS), no-tillage with mulching (W_ntS), tillage without mulching (W_t) and no-tillage without mulching (W_nt), was conducted at the State Experimental Station for Agro-Ecology in Fengqiu, Henan Province. Soil samples were collected from the plots of the four treatments, incubated in CMC-Na Congo red medium for counting of CDB and analyzed with PCR-RFLP for effects of no-tillage and straw mulching on CDB community. 【Result】The results of plate counting show that the population of CDB was 8.40×107 (W_tS ), 11.4×107 (W_ntS), 4.57×107 (W_t) and 5.27×107 (W_nt), indicating that both No-tillage and straw mulching increased the number of CDB to a varying extent. Out of the soil samples collected from the four treatment plots, a total of 425 strains of CDB were isolated, 4 CDB gene libraries built based on treatment, and a total of 33 OTUs obtained. The number of OTUs of CDB in the treatments range from 19 to 26, among which 7 were found common in all the 4 treatments. 8 particular in the treatments with straw mulching soil and 3 in the treatments of no-tillage, which indicates that the practices of straw mulching and no-tillage did have some effects on CDB community structure in the soil. The 4 clone libraries varied sharply in CDB diversity index, which was the highest in Treatment W_ntS, and higher in the two treatments with straw mulching than in the two without straw mulching, which indicates that compared with tillage, no-tillage is more conducive to diversity of the CDB in the soil. Phylogenic analysis shows that the CDB in the soils varied in the range of 80% ~ 99% in 16S rDNA homology. The 33 OTUs could be sorted into 4 phyla, 7 classes, 11 orders, 15 families and 20 genera. Proteobacteria is the dominant phylum, composed of 15 OTUs, which could be sorted into 11 genera. In Treatment W_tS, Sphingobium, Stretomycetacea, Sinorhizobium and Promicromonsporaceae are the dominant groups, accounting for 67.92%, in Treatment W_ntS, Stretomycetaceae, Promicromonsporaceae and Flavobacterium are, accounting for 48.15%, in Treatment W_t, Sinorhizobium, Promicromonsporaceae and Acinetobacter are, accounting for 54.29%, and in Treatment W_nt, Rhizobium, Phyllobacterium, Pseudomonas and Promicromonsporaceae are, accounting for 63.21%. The treatments with straw mulching are significantly higher than the treatments without straw mulching in relative abundance of Stretomycetaceae,Flavobacterium and Sphingobium, which indicates that straw mulching is conducive to growth of these bacteria, which play an important role in straw decomposition. And the treatments of no-tillage are apparently higher than the treatments of tillage in relative abundance of Pseudomonas, Phyllobacterium, Paenibacillus, Promicromonosporaceae and Sphingobacterium, which indicates that no-tillage is conductive to growth of these bacteria. Canonical correspondence analysis shows that great changes have taken place in CDB community structure in all the four treatments, that pH, TP, organic carbon and TK is significantly and positively related to no-tillage and that TN, analyzable N, readily available K, readily available P and organic carbon is significantly and positively related to straw mulching. 【Conclusion】It is quite clear that no-tillage and straw mulching can significantly raise the number and diversity of cellulose-decomposing bacteria in the soil, and alter cellulose-decomposing bacteria community structure. Conducted as key techniques for sustainable agriculture to improve soil quality by increasing the number and variety of microorganisms, no-tillage and straw mulching or incorporation do have some theoretical significance and enormous potential for extrapolation.