Biochar is a carbon-rich solid material produced from incomplete combustion of biomass. Owning to its unique properties in soil amendment, mitigation of greenhouse gases and increase of soil carbon stock, it plays a more and more important role in environmental science. However, until now the impact of biochar application on soil properties has not been fully understood, and many mechanisms are still unclear. Soil microbe is the significant pusher in the circulation of chemical substances and its activity is an indicator of soil quality. In recently years, culture-independent molecular techniques including terminal restriction fragment length polymorphism (T-RFLP), cloning, denaturing gradient gel electrophoresis (DGGE) have been widely employed to study the diversity of soil microbe.In this study, soils samples were collected from paddy-upland rotation experiment, six treatments were established, including: No fertilizer (CK1), Regular fertilizing (chemical NPK, CK2), Straw returning to field + regular fertilizing (T1), Rice straw biochar + regular fertilizing (T2), Rice straw biochar + 70% regular fertilizing (T3), Garbage biochar + regular fertilizing (T4). The nutrient indexes of soil, such as total nitrogen (TN), available K and available P were measured with standard experimental methods. Molecular biology technique of PCR-DGGE was used to characterize the diversity of soil bacteria. Quantity One Software was used to analyze electrophoretogram. The DGGE fingerprinting profile of bacterial indicated the composition and distribution of bands of six treatments. The number of DGGE bands of fertilizer treatments (CK2、T1-T4)was more than CK1's. The intensity of some bands (band 3, 4, 5, 6) of biochar treatments (T2-T4) increased and some specific bands appeared in rice straw biochar + 70% regular fertilizing treatment (T3), indicating the structure of soil microbial community had been obviously influenced by the addition of biochar and fertilizer. The similarity of bacterial community among six treatments was higher than 48.6%, and the results of cluster analysis have shown that the bacterial community of seven treatments could be divided into four clusters. The bacterial community of Rice straw biochar (T2, T3) belonged to one cluster, while the bacterial community of Garbage biochar (T4) and Straw returning to soil (T1) were in a same cluster, and the bacterial community of CK1 and the bacterial community of CK2 belonged to individual cluster. Shannon diversity indices calculated from DGGE profiles indicated that the abundances of T1, T2, T3 and T4 were much higher than the abundances of CK1's and CK2's. Statistics analysis showed that there was positive correlation between Shannon diversity indices(H) and species richness (S), and the correlation coefficient was 0.939 (P=0.000 < 0.01). Study on correlation between soil nutrients and the diversity of soil microorganisms found that the diversity of soil microorganisms among the six treatments was closely related to the soil properties. In summary, biochar treatments played an active role in the development of diversity of bacterial community in the soil, while the straw returning to field treatment showed less influence on it. Those results provided a scientific basis for field application of biomass.